Imagine a dialogue where Marcus introduces his colleague Sam to somebody.
Marcus says, "This is Sam, he's a real hard worker." Sam says, "Excuse me, I'm a woman and prefer female pronouns". Marcus says, "Uh, yeah right. I don't believe you."
Who's the unreasonable party, here? Is it Sam, who's stated their identity and preference? Or is it Marcus, who feels like Sam needs to do something to convince him of her femininity? Why is Marcus's belief about Sam's identity the record as opposed to the statement from the primary source?
You've said that your issue here is that people get corrected in impolite ways, but if people just _believed everybody when somebody stated a pronoun preference_, that problem would go away.