I guess I would be on board with this if “biological sex” (as some term in) were a binary, but it isn’t. For example, there was a big dust up last year in the run up to the olympics over a female athlete whom authorities deemed had too much natural testosterone in her system to be deemed fit to compete as a woman… but at the same time we’re definitely talking about this person competing at a level of sports where genetics is often rewarded.
So where then do we draw the line? at a certain level of hormones? a certain bone structure? hip size? All of these are variable as well. There exist people who have both sets of genitalia. Because clearly genitalia isn’t enough.
I guess what I’m saying here is, from a purely biological point of view, sexuality exists on a spectrum, not a binary. It’s not necessarily one or the other. It only exists our heads that way because society-at-large has done its level best to make sure these people are invisible. And given the state of said “society”, that’s probably best for these folks to remain invisible, given even the opinions expressed here seem to indicate a level of distain for people who identify outside the “mainstream”.