"This isn't about a community no matter how much you'd prefer otherwise."

Except that it was/is about the community/movement/group collectively known as skeptics. Go back the the beginning of the conversation. I mentioned materials and the reply came back about how it was all transphobic misogynist stuff. Well there is nothing inherently transphobic or misogynist about the application of epistemology, logic and spotting logical fallacies so the complaint must have been about the people. Then the conversation explicitly mentioned people by name as representatives of the community. So no matter how much you try to say it wasn't about the community it was.

"This was a conversation in a public forum. The word "sceptic" has a generally understood meaning."

There are lots of "generally understood" groups that go by existing words that aren't understood at all by the general population. To many people atheists are Satan worshipers, trans people are bathroom predators, and geologists are part of a massive cover-up about the truth of young earth creationism. But we know that these "generally understood" meanings are completely false. In a dictionary a word can have more than one meaning and context matters.