This feels like a bit of a bikeshed. There are problems with many configuration languages. I don't see anything related to yaml on their issue tracker.
Look, without getting into a debate on cancel culture, I’m wondering if it’s specifically virtue signaling that you object to. Because RMS is specifically known for a massive amount of virtue signaling. It’s all over his website and was written all over his office at MIT. And he would join discussions and change the subject to whatever he felt like talking about in order to, we’ll, spread the good word. And of course the free software movement more broadly is about taking a moral stance and aggressively spreading it through copyleft and other forms of activism.
So I wonder if it’s not “virtue signaling” here that’s the problem, but the virtue being signaled itself that you don’t like.