Nobody de-federated. People saw that there was a the_Donald community on sh.itjust.works + a lot of people from said server defending it ("just ignore it bro"). That triggered probably bad memories ala spez defending t_D because of "VaLuABlE DiSCuSsIoN", while they brigaded and harrased countless people during their time on Reddit. Some people got a little bit carried away and demanded de-federation and a couple of trolls throw gazoline in the fire.
Oh boy. Some survivors will need a lot of therapy after this.