Right? We already do this with names. "Please don't call me Bill, I prefer William". Ok, I'll call that person William. It'd be an asshole move to deliberately

Right? We already do this with names. "Please don't call me Bill, I prefer William". Ok, I'll call that person William. It'd be an asshole move to deliberately call them Bill. Using someone's correct pronouns is the same. If they say, "use x not y" it's an asshole move to deliberately not use x.