> unrelenting deluge of obnoxious / disturbing / spam-filled / miserable race to the bottom of the lizard brain stuff that is constantly being pushed back on any moderately popular social media site.

I keep hearing this, and it makes no sense.

1) Add a block button. 2) Don't surface random content to users. 3) (Optional) hard restrictions on private messages.

This solves the issue entirely, with no need to moderate anything that isn't illegal.

The simple fact is that this is a really easy problem to solve. Companies just don't want to implement 2).