Youtube comments used to be known as a cesspool, but lately I'm mostly avoiding them for their unbearable positivity and uncritical praise of the video. I can see how that's bad on conspiracy or racist videos though.
I wonder if this is because the creators routinely prune negative comments of them. Or perhaps it is because Youtube severely down ranks comments with dislikes.
Fascinating, I'd guess this to be the result of a filter bubble? i.e. it would only show you things you agree with. That might not be optimal though (at least in terms of harvesting human attention at all costs), I always heard that outrage drives engagement better?