I'm fairly sure I've read more of the scholarly literature on the subject than 2 people who had never heard of sexual orientation as a social construct and did not know what word “essentialist” means until this conversation, or anyone who claims that there are “gay animals”. I've read dozens of the relevant studies, and I cannot confirm your claims for you to the extent that they are intelligible at all because I know that they are false. Ask me about the seasonal variation in the size of the INAH3 in sheep's brains.
The biological studies on humans invariably treat sexual orientation as a binary, and employ a disease model methodology, where “heterosexual” is considered the norm and “homosexual” is any deviancy from the norm. The methodology in which sexual orientation is considered binary is a critical flaw in all such studies that claim to have found a correlation between sexual orientation designations and some biological feature--in the same way, if one were to classify school children according a binary of sock colors--i.e., ”light” vs. “dark” socks--one can undoubtedly find all sorts of statistically significant correlations that have nothing to do with the socks they are wearing, correlations that disappear when one divides their sock colors into, say, 7 different colors.
Neither the term “sexual orientation” nor any particular designations for sexual orientation are scientific terms; many different definitions and concepts for these terms are used in the various studies to the extent that there is any attempt to define the terms at all. In most such studies, rarely is there any inquiry to ascertain subjects' sexual orientation beyond asking a few questions. There is no objective method to determine whether a person belongs in any particular category of sexual orientation.
No biological study has ever acquired findings by which to deduce that sexual orientation is an immutable trait. No study has acquired findings by which to deduce that sexual orientation is something other than a social construct. In contrast, the historical evidence is overwhelming and unequivocal that in cultures that did not consider categories of sexual orientation as immutable traits, people did not behave as though they have any such immutable trait of sexual orientation. But, then, even in current cultures where many people consider sexual orientation an immutable trait, a significant portion of people similarly exhibit behavior inconsistent with that belief, changing the designations by which they identify, or eschewing self-identification as any sexual orientation category altogether.
Anyone claiming the sexual orientation is an immutable biological trait needs to account for the overwhelming and unequivocal evidence showing that people in cultures that did not have sexual orientation categories did not behave in accordance with either monosexual orientation category. Neither you nor Unveiled Artist has even mentioned this evidence, much less accounted for it.