Michael Seto, in his article "Is Pedophilia a Sexual Orientation?" ("Archives of Sexual Behavior, Feb. 2012, Vol. 41, Issue 1, pp. 231-236), makes a distinction between sexual gender orientation, and sexual age orientation, and discusses the potential legal implications of expanding the definition of "sexual orientation" to include sexual age preferences. Here are some excerpts.

http://link.springer.com/article/10.1007/s10508-011-9882-6 You can use Sci Hub to retrieve the entire article. http://sci-hub.bz/ Maybe this direct link will work: http://link.springer.com.sci-hub.bz/article/10.1007/s10508-011-9882-6

"Answering the question of whether pedophilia in men is a sexual age orientation (or sexual orientation with regard to age) has implications for science, clinical practice, and public policy…

"Sexual gender orientation (heterosexual or non-heterosexual preferences) is typically experienced as something one begins to discover about oneself in early puberty, rather than something one acquires as a result of developmental or environmental processes. An increasing body of research has revealed that prenatal factors (e.g., as indicated by the fraternal birth order effect and greater non-right-handedness) influence sexual gender orientation and has identified neuroanatomical and other biological correlates (Mustanski, Chivers, & Bailey, 2002; Wilson & Rahman, 2005). Recent research suggests some interesting similarities, and differences, in the neurobiological correlates of pedophilia (see Cantor, submitted). For clinical practice, the answer shapes our hypotheses and approaches about assessment, prognosis, and treatment. Sexual gender orientation is often viewed as innate; it can be assessed through self-report, reaction time, and genital response; and reorientation therapies have not worked for homosexual men, suggesting interventions may be able to change sexual arousal patterns or even behavior without changing the underlying preferences (Drescher & Zucker, 2006). Finally, for public policy, perhaps most controversially, the answer may affect societal perceptions and may have implications for criminal and civil law. Anti-discrimination laws and policies refer to sexual orientation, but with the implicit understanding that one is referring to sexual gender orientation. But what might happen if the definition of sexual orientation were to expand to include sexual age preferences such as pedophilia?...

"By the above definition of sexual orientation—and most common definitions of sexual orientation—pedophilia can be viewed as a sexual age orientation based on the more limited evidence available regarding its age of onset, associations with sexual and romantic behavior, and stability over time. Though there are clearly differences in some respects, there are also striking similarities in the research literature on pedophilia….

"The strongest test of sexual orientation is whom a person would choose in a hypothetical situation where they could freely have sex, without negative consequences, when presented with the alternate choices: man or woman, adult or child. Teleiophilic individuals (to use a term coined by Blanchard) would choose physically mature persons and pedophilic individuals would choose prepubescent children. Androphilic (homosexual teleiophilic) men would choose other men and gynephilic (heterosexual teleiophilic) men would choose women.2

"Sexual age and gender orientation can be viewed as dissociable in men (see Fig. 1; Blanchard, 2010; also, Quinsey & Lalumière, 1995, described a male sexual preference system that would contain different mental modules attending to different gender and age cues). Whether someone is sexually attracted to children or to adults is partially independent of whether he is sexually attracted to males or females. These dimensions are not completely orthogonal because pedophilic individuals distinguish less between boys and girls than teleiophiles distinguish between men and women, possibly reflecting the fact that boys and girls differ less in terms of body size and shape than do men and women. Secondary sexual development (breasts, axillary and pubic hair, size and shape of external genitalia) also provides more cues about gender when examining adults.

"I have focused on the scientific and clinical implications of conceptualizing pedophilia as a sexual orientation in this brief article. But what about the legal and social implications? In particular,what impact might there be inconceptualizing pedophilia as a sexual age orientation, based on empirical evidence, akin to sexual gender orientation such as heterosexuality or homosexuality? For example, there are anti-discrimination laws or policies that specifically mention ‘sexual orientation’ as grounds for redress. The makers of these laws and policies surely had sexual gender orientation in mind, not sexual age orientation.

"It is important to emphasize here that I am not equating these gender and age orientations. Homosexuality continues to be negatively sanctioned in a variety of ways, but social changes haveoccurred, including the legal rights of marriage or civil unions in Canada and several other countries, recognition of same-sex partner benefits, and the inclusion of sexual gender orientation in anti-discrimination policies and laws. In my opinion, these are signs of progress: I am generally opposed to discrimination, and I believe that mutually consenting sex between adults should not be subject to legal or other discrimination. Pedophilia, on the other hand, involves sex between an adult and a child who is not legally able to consent. There are substantial asymmetries in cognitive ability, psychosexual development, and autonomy that are not usually present in sexual interactions between consenting adults. I would still consider it no particular concern of mine if adult pedophiles advocated for the freedom to have sex with other adult pedophiles. They do not, however, and I think there is often a self-serving motive in adult statements supportive of adult–child sex.3"

From wiki, you'll notice that the term is actually very broadly defined:

Sexual orientation is traditionally defined as including heterosexuality, bisexuality, and homosexuality, while asexuality is considered the fourth category of sexual orientation by some researchers and has been defined as the absence of a traditional sexual orientation. An asexual has little to no sexual attraction to people.[4][19] It may be considered a lack of a sexual orientation,[20] and there is significant debate over whether or not it is a sexual orientation.[3][4] Most definitions of sexual orientation include a psychological component, such as the direction of an individual's erotic desires, or a behavioral component, which focuses on the sex of the individual's sexual partner/s. Some people prefer simply to follow an individual's self-definition or identity. Scientific and professional understanding is that "the core attractions that form the basis for adult sexual orientation typically emerge between middle childhood and early adolescence".[1] Sexual orientation differs from sexual identity in that it encompasses relationships with others, while sexual identity is a concept of self. The American Psychological Association states that "[s]exual orientation refers to an enduring pattern of emotional, romantic, and/or sexual attractions to men, women, or both sexes" and that "[t]his range of behaviors and attractions has been described in various cultures and nations throughout the world. Many cultures use identity labels to describe people who express these attractions. In the United States, the most frequent labels are lesbians (women attracted to women), gay men (men attracted to men), and bisexual people (men or women attracted to both sexes). However, some people may use different labels or none at all". They additionally state that sexual orientation "is distinct from other components of sex and gender, including biological sex (the anatomical, physiological, and genetic characteristics associated with being male or female), gender identity (the psychological sense of being male or female), and social gender role (the cultural norms that define feminine and masculine behavior)".[1] According to psychologists, sexual orientation also refers to a person’s choice of sexual partners, who may be homosexual, heterosexual, or bisexual.[21][22][23] Sexual identity and sexual behavior are closely related to sexual orientation, but they are distinguished, with sexual identity referring to an individual's conception of themselves, behavior referring to actual sexual acts performed by the individual, and orientation referring to "fantasies, attachments and longings."[24] Individuals may or may not express their sexual orientation in their behaviors.[1] People who have a homosexual sexual orientation that does not align with their sexual identity are sometimes referred to as 'closeted'. The term may, however, reflect a certain cultural context and particular stage of transition in societies which are gradually dealing with integrating sexual minorities. In studies related to sexual orientation, when dealing with the degree to which a person's sexual attractions, behaviors and identity match, scientists usually use the terms concordance or discordance. Thus, a woman who is attracted to other women, but calls herself heterosexual and only has sexual relations with men, can be said to experience discordance between her sexual orientation (homosexual or lesbian) and her sexual identity and behaviors (heterosexual).[25] Sexual identity may also be used to describe a person's perception of his or her own sex, rather than sexual orientation. The term sexual preference has a similar meaning to sexual orientation, and the two terms are often used interchangeably, but sexual preference suggests a degree of voluntary choice.[8] The term has been a listed by the American Psychological Association's Committee on Gay and Lesbian Concerns as a wording that advances a "heterosexual bias".[

That link you provided is in the context of homosexuality. Pedophilia is not legal so the definition provided by the APA reflects that. You need to understand how the mental health professions operate. Definitions are not fixed in stone and are constantly updated.

Here is an article from 2013 where the APA says they will reword their definition of pedophilia after a public outcry. https://archive.is/4SFFh. That was a few years after the 2009 bill debate. They could always change their minds again. As I said, it's more to do with politics than science as the brain and mental world are still not well understood.