I take your point. Yes, we don't need "proof" or validation from other forms of nature in order to accept and celebrate diversity right here in our own human race.
This article was written (partially) in response to a local political issue where a university professor was hosting a lecture about the "economic interests involved in transgenderism", including arguments that the medical industry and the biotechnology industries were "pushing" the trans "agenda" for their own profits (rather than providing gender-affirming care). I alluded to this under the heading transphobia disguised as intellectual exploration.
Part of my intent was to highlight that trans lives have always existed, and there aren't more trans people as a result of the availability of some gender-affirming medical options. It felt necessary to address the existence of transgenders in other species because a common anti-trans argument stems from the B.S. that it's "not natural" etc.