I've given the title of this thread a lot of thought and thank
@crimsonaudio for that mental exercise.
I've come to the conclusion that social media don't destroy humanity. Rather, they reveal humanity by removing any filter.
The outlandish positions, statements and endless provocations are what humans do when they don't think they'll be called to personal account for their actions.
For goodness sake, how many criminals are caught because of what they posted on one forum or another? It honestly never occurs to them that their statements are public record.
There are exceptions, of course, where social media facilitate either physical or mental rescues. But there are far more examples of feeding the maw.
When people are behind a keyboard, not face-to-face with the people they insult, condemn, or otherwise denigrate, they'll say things they'd never say in a different setting. It's exactly parallel to what goes through your mind, unvoiced, in a personal confrontation. Except there is no filter because there are no perceived consequences, real or potential.
To quote the famous philosopher Pogo (for the non-OFC, look him up), "We have met the enemy, and he is us."
It's a crying shame, but social media are not the destruction of humanity. They're who we really are, and always have been, when we think we can get away with it.