I don’t understand how this question can follow. Are you suggesting that social media simply must optimize for engagement and not pay attention to negative consequences?
What does that mean? Like, we want the Facebook mods to delete anything that's too depressing? Sounds more dystopian rather than less... and I thought we were supposed to be worried about "duck syndrome" where everyone appears to be having great lives, making you feel bad, because you don't see the negatives (like a duck paddling underwater, see?).