I wanted to share my response about how singular they/them pronouns are grammatically correct.
tldr: You've been using singular they for people of unknown gender for awhile, you just might not have noticed it because it's built into the English language. When you say you won't use they/them for someone who's requested those pronouns because it's "grammatically incorrect", you're probably just transphobic.
Singular they/them pronouns are grammatically accurate. When one doesn't know the gender or pronouns of a stranger, they'll refer to them as "they". I would come up with an example, but that last sentence is one. For the most part, the protests against singular they for grammatical reasons seem to me like they're coming from a place of resistance out of unfamiliarity. It's possible that you don't want singular they pronouns to be grammatically correct because you're used to addressing people only as "he" or "she". But binary gender is a construct that's crumbling, and nonbinary people have existed as long as the binary. It's time they get some recognition.
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