I didn't say anything about forbidden topics. This is about comment quality, not topic. Note this, for example, from https://news.ycombinator.com/newsguidelines.html:

"Comments should get more thoughtful and substantive, not less, as a topic gets more divisive."

Re flamebait: I'm talking about what leads to flamewars in the statistical case. Suppose you drop a lit match in a dry forest. The argument "but it didn't cause a wildfire" is not a good one.