The Left didn't get their way and they are pissed. There is a mindset that is thrilled by acting out, tantrum throwing, and violence. That takes their minds off of the losers that they are - their own abject laziness and inability to create a good and wholesome life for themselves.
They prefer to conjure up diseases (mental, sexual, gender-related, substance-related) and other people (rich, white, privileged) who have ruined their life and to whom their victimhood is blamed.
When Obama was elected, quite a few people didn't agree with his weakness and protective stances toward terrorism,his racist-mindedness, his America-hating agenda, but those people weren't the kind who felt violence was the answer. They sought legal means of thwarting Obama's terrible agenda.
Those on the Left think violence first. So that's where it's going now and although I thought maybe Trump would be able to turn it around, I am now thinking that the Left is just too barbaric, uncivilized and, (frankly) just too stupid to turn around and find a better way.