jducoeur

* Several of the newsgroups I was in died not because of the Inevitable Death of Usenet, but because of specific people who dominated conversations with their personal ideology. They weren't "toxic" in the obvious sense; they were simply deeply committed to an ideology that was at odds with other posters and also capable of writing large volumes of posts, and the result was that conversations in the group became more and more dominated by debating their ideology. All of this was nominally on-topic, and the "death" of the group wasn't visible in a decline in posts, but thoughtful discussion of any other topic got derailed enough that people stopped writing it.

If you haven't read it, I commend this article on "toxic influencers". It's not quite specifically talking about the same effect you are, but I think there's some overlap in terms of the personalities involved.