I actually have a ton experience modding for small streamers, and by that I mean that the biggest streamer I've ever modded for had, at that time, an average of ~40–50 concurrent viewers by my estimate. I can't imagine modding for any of the big streamers.
Anyway, I love this story.
I usually have the pronouns extension installed (the only reason why I don't at the moment is because I've been highly experimental with web browsers recently, lol). I don't add my own pronouns, if only for the entirely petty reason that my name on Twitch is already so long that merely putting "He/Him" behind it is, in a lot of cases, all it takes to push part of it but not all of it onto the next line—which looks ridiculous. I still like being able to see other peoples' pronouns, though. Pronouns in English have always been somewhat awkward because English is very awkward. That's no one's fault, though, and I don't think that's what most if any of the people who outed themselves were complaining about. I can picture exactly the kind of person who would protest something like that.
It really makes me wonder how many people are prejudice to that effect as well, but who are also smart and/or self aware enough to keep that to keep that to themselves in the presence of those who would not agree. Surely—the number of people who actively hide prejudice in plain sight, who actually exist and not only in theory, is non-zero. It has to be.