The group has denied racism but has been listed as a hate group by the SPLC for its anti-immigrant, Islamophobic policies, and routinely attaches itself to neo-Nazi rallies. And while it claims to use violence in self-defense, it has a long history of participating in violent marches (including the fatal Charlottesville rally from a year earlier) and has explicitly promoted violence. “Fighting solves everything,” McInnes has said multiple times. Some of its members have instigated fights, and it runs a paramilitary training group.
McInnes tried to pin the bans on a “conservative purge” rather than his group’s violent behavior. He claimed it would have “zero effect” on the Proud Boys and mulled a lawsuit against Twitter, although it’s not clear that much could happen when Twitter could point to multiple examples of policy violations.
It’s not certain the ban was meant to dovetail with the Washington rally. However, it’s hard to escape the timing. It suggests that Twitter doesn’t want to wait until there’s more Charlottesville-level bloodshed before clamping down, even if the group’s violent tendencies have been clear for a while.