Yes. I am absolutely aware of that tragedy like I am aware of the white supremacist Dylaan Roof who shot African-Americans in a South Carolina church. But I'm talking about organized groups, not lone wolves. And I did use the words "usually" and "can". Antifa provides security to anti-facists groups and responds with violence when the other side initiates it. There's a good article in The Economist on the Antifa. They also don't carry clubs, shields and automatics weapons like the militia groups, neo-nazi and white supremacist groups did in Charlottesville. I fear however that Antifa will likely carry weapons too now and abandon their "use violence only when provoked" rule because of Charlottesville.