theunitofcaring:

The other part of the picture is that, once a group has “we try to hurt our enemies’ feelings” as a norm, it will attract people who want to do that, whether they share the groups’ values or not. Lots and lots of people choose political affiliations based on which ones let them behave the way they want to behave; a cost of tolerating lots of behavior from ‘your side’ is that you get a lot of people who are there for your tolerance.