That Gamer article unironically reads like a false flag in some places to make trans people even more hated, which actually has happened during all this nonsense.
People have planted their flags, and they did it in the most annoying and inefficient way possible that I'm actually kind of amazed. Modern activists in general are pretty awful at getting people on their side, but this is another level. A combination of slacktivism, poorly-chosen targets, and just pure malice of consumers rather than any kind of viable end goal that would help trans people has made this probably the biggest boycott backfire in gaming (even more than the MW2 one). When you go after consumers of an entry in a globally beloved franchise that the original hateful creator had nothing to do with, does not change her plans regardless of the product's success, and has no hateful content without a reach that requires knowledge of historical tropes barely anyone in the modern era cares about, people aren't going to be happy. The entire basis of the boycott isn't even a call to action on policy change or anything, it's purely a judgement call on consumers. It's the terminally online version of someone protesting the auto industry by keying some random person's used car they could barely afford. People aren't going to think about the "cause" you're fighting for when they see your behavior, they're going to think you're an asshole.
That said, the idea that any more than 500k of that 12 million are even AWARE of the controversy with JKR is similarly absurd. I'd almost say that article author WANTS the entire userbase to be a group of apathetic centrists who were told the plight of their poor trans friends and then threw them aside because "silly wizard game more important!". Anything to make yourself out to be a victim. And even if you are one, it's certainly not because of this game. There is not a single other marginalized group in history that has wasted this much energy on a piece of media tangentially related to their marginalization. Hell, not even minstrel shows got this level of pushback since there was more productive shit for black people in the jim crow era to do, and those shows were far more worthy of being attacked than anything Rowling could come up with.