The Wikipedia has a lot of citations to back it up, so it's not completely off-the-cuff op-ed. I'm sure the antifas will try to water it down, though.
One thing I would take issue with is describing the antifa movement (at least in the U.S.) as "anti-government." They aren't so much anti-government as they are anti-Trump administration government. They didn't materialize until after Trump's inauguration.