Yeah, I have a few thoughts on this issue. It's on the ever-growing list of things I want to write about. I think yyou're absolutely right. Pronouns have always been about utility for the user and socially agreed upon definitions of what a "he" or a "she" looks like for reference/identification purposes. I don't need to declare my pronouns because everybody who looks at me will immediately recognise me as a male. If somebody started calling me "she" I'd be bemused. Not offended.

This is true for some trans people too, of course. I might see a trans woman and be completely unable to tell she's trans and so refer to her as "she." Or I might think a man with long hair is a "she" from a distance and realise, up close he's a "he."

In each case, the pronoun used is about my perception. If my perception is wrong (or doesn't correspond with the way they see themselves) and I was corrected, I'd be an asshole if I insisted on sticking to my original usage. But that doesn't change the fact that our original perception will almost always be correct. Human beings are very well evolutionarily adapted to tell the difference between males and females.

Speaking of assholes, it's endlessly fascinating to me that we only grant this linguistic control for gender pronouns. Just as with "he" and "she" whether or not I call somebody an "asshole" is up to me. I don't need to ask permission. I don't need to check if the person identifies as an asshole, I get to use language in the way I feel is appropriate. That we live in a world where it's less controverisal to call somebody and asshole than to call certain males "he" is an interesting turn of events.