Why would we need first names to demarcate gender identity in a consistent way in order to use they/them for everyone? In my native language we have some names that are more ambivalent about gender than others and we’re doing just fine with a single genderless third person singular pronoun.

I suspect that a lot of cis people would be pissed about being referred to as they/them as well, but they can suck it up. I said this in a different comment here, but I can see that being useful with people who are stuck on that he/she framework. But I still think of this as an unnecessary one step back to take two steps forward, when it could just be taking one step forward.