This sort of thing has been on the rise for a while.
The internet/social media has convinced people to pick a side in any sort of conflict and then demonise and dehumanise the other side. Once the dehumanisation starts, it's easier to convince people that violence against the other side is OK.
For example, the craze of milkshaking people a few years ago. Loads of people found it funny because it was being done to right-wing people, they never thought any further than it happening to someone they don't like. Then it moves onto to 'punch a nazi' where the nazi's in question are women that don't believe people can change sex.
It's a terrible slippery slope to go down but people just don't see it, and they won't until it affects them personally.
It's a scary time.