Socialists aren't violent like white supremacists. Those days are gone the majority are peaceful, and not murdering based on skin color.
White Supremacists however....
You know what, I am not endorsing white supremacists in any way (it's hard for me to talk about politics of a country that's 7000 kilometers away) but I remember how Antifa started a massive riot during the 2011 independence march, including bringing violent militant leftists from Germany especially to organize a riot, and targeted... a reenactment group of all the parties. I remember how, during the recent G8 summit in Germany, ANTIFA made the entire city look like after an allied bombing during world war two. That aside from recent militant activities of ANTIFA in US, because the US ANTIFA fashion is considerably recent comparing to what ANTIFA had been doing in Europe for decades before... And that skips a long history of far-left terror movements like RAF or the Red Brigades, which dominated the world of terrorism before the emergence of the modern Islamist movements.
I would also like to remind you that ANTIFA is a brand, not name of an unified group with a specified structure. This shows just sheer range of the phenomenon of violent far left that very often can't distinguish between a nazi and a normal right wing conservative, and attacks everyone it dislikes indiscriminately.