Is rejection of people such as homosexuals or in particular transgender they function of biology as well just in as much as an ugly person may not gain as much acceptance as someone who is considered to be beautiful in their external appearance.
Consider the reversion the sun have described as a result of seeing what is called public displays of affection, consider the revulsion some describe when seeing people with obese bodies displaying much of their bodies in public. Likewise consider the reversion and seeing someone who is starving themselves such as an anorexic body which is nothing but skin and bones. The point is that the body has mechanisms to find certain things revolting and if you're still not convinced consider that the smell of death a particular molecule in fact is revolting to most of us. Consider whether in the selection of your mate appearance was a factor. If your mate had an extra 200 pounds on their body would you have accepted them?
What level this Rivocean function is biological or mental it's hard to say and it may differ from person to person yes I will explain.
As with taxes each of us have to draw a line somewhere, surely, a tax rate of 100% is not acceptable, nor is one of 99%, likewise the body mechanism itself if it is true that I have certain evolutionary components built into it, then would it not be natural for traject qualities which do not result in the continued propagation of the gene pool. This assumes of course that we are nothing more than advanced animals . I would counter that we have an animal side and then another side that can also be evolved. Evolution of this mental side may include rejection of more baselevel circuitry in our body apparatus which provides a good part of the code for our minds, to start.
And my own journey I'm slowly but Shirley learning as I encounter different mindsets that each one tends to contain a certain nugget of truth although like Princess P it may be wrapped in layers upon layers of other things. The golden is to dig for the nugget of gold, to find the element of truth buried in those perspectives that one may encounter in life. Mother nature or God or whatever term you prefer has Shirley formed such individuals in the same way they have formed yourself.