[intended]

Theres 3 (4?) horse men of online communities.

1 Identity topics, eg: Politics/Religion

2 Insufficient moderation

3 NSFW content

4 Inability to distinguish experienced commenters or valid content from plausible sounding content. I.E. Low Subject Expertise thresholds.

4 is what keeps a community boring, while keeping the SNR high.

[IAmBroom]

I tried in vain to understand what centaur-like men had to do with your point.

"Horsemen", as in the Apocalyptic Tetrad?