We don't want mobs on HN. There was very clearly a mob dynamic happening in the replies.

Edit: there was another case of this recently:

https://news.ycombinator.com/item?id=47576107

https://news.ycombinator.com/item?id=47576084

The point is that mob dynamics do more damage to the community than the threads add value, and protecting the community has to be the high-order bit.