I'm one of those people that prefers to have my name used instead of she/her or they/them, and it works quite well once people shake the cobwebs off their brains.
However, living your life as "he" while knowing you are "she" is full of moments that hurt. The English language may not require the distinction, but in practice it is how we define people. Why would you continue to hurt someone by using a pronoun that isn't what they've described themselves as? It's like someone who has gotten your name wrong, and no matter how often you correct them, they continue to call you the wrong name. Except it isn't just one person, it's a class of people that is filled with both those that hate your existence and those who refuse to understand it.
I literally said "some people", because there are certainly some who don't care if people call them "they". Like I straight up acknowledged that in my first sentence. My point was that it isn't going to jive with everyone, and that maybe people should reconsider that safety blanket of "non gendering".
How is "just using they/them for everyone" not "misgendering because it's easier"? Because asking someone what their preferred pronouns are is too hard for many