@WrenArcher I would argue the reason some people are offended is because it’s disruptive to their identities. It’s in the way the word is used.
They’ve been a "man" or "woman" for all their live, now suddenly they’re supposed to something else, according to this loud internet minority? A "cis person"? Maybe even "just" a cis person? "What’s that even supposed to mean? I’m a woman!"
I think we should accept that some people just think like that, and not immediately ascribe a trans-hate to them.