[pygy_]

> the implication is that controversial or provocative posts get pruned from facebook (or at least buried under a view more comments button) and the less controversial ones rise to the top.

AFAIK, it is more complex than that, and the description of the author is correct:

A "bad" comment is moderated away for everyone but its author and his/her the friends.

[leeoniya]

looks like hellbanning just leveled up.