Exactly, I think you are one of the people who gets it. I didn't put it in this article, but it has occurred to me that maybe some right-wing groups actually help fund Antifa, Women's etc. Studies Departments, websites that advocate SJW causes, and so on. It would really be a stroke of political genius. For all that most Leftists talk about "Left Unity", Antifa is the perfect way to break that up. In the U.S., I think a large part of why working class people voted for Trump is because he was anti-SJW. That's not the majority of it, but that group of voters was enough to make the difference I bet. People don't like being told what they can and can't talk about, and when they see crazy shit like this, they naturally want to fight back against it. If Left-leaning people do not denounce Antifa, then the Right-Wing looks like the only option if people want to fight against this. Like you said, it also justifies Right-Wingers talking about Marxist infiltration of the government and how everybody Left-of-Center is a secret commie. That hasn't become true, but now it looks like it to a lot of people.

Another think you brought up is also very important - these people never manage to touch the establishment. What change do they really threaten? I guess they want to launch a Communist Revolution, but that is never going to happen, so the only people who need fear them are other grassroots activists who disagree with them. They divide anyone who isn't part of the establishment - anyone who doesn't have power already. They ultimately help keep society as it is, except for all the poor activists and freedom of speech that get crushed along the way.