Yep, pretty much what UNY0N said. It is about the gender, not the pronouns per se. It is an English thing that they have gendered pronouns when mostly all other stuff in the language is (assumed not) gendered. Such meticulus discussion of pronouns detached from gender makes me wonder what your reaction would be if someone held a door open for you and then called you Fraulein. Would you feel misgendered then?
Like this is a question that people ask and not a troll ragebait. People most positively misgender on purpose upon inspection that a person is trans. If a cis person says “but I am a boy” they will bend over apologizing.