It's not much different than the KKK which since the 50s onward since the actual, national Ku Klux Klan dissolved during World War II. It was a bunch of groups which claimed to be the successor to that national Klan but were regional at best. Like how you don't have a group called the "Ku Klan Klan" (since there's dozens of Klans out there), you don't have a group called "Anti-Fascist Action". But you do have plenty of groups like TORCH Network, BAMN, Rose City Antifa, and similar groups which are like your local Klans and actually do exist as groups.
And hell, not every KKK member in the 50s was the sort who showed up at civil rights protests to beat people up or cheered on little black girls being blown up. Senator Robert Byrd was a supporter after all (although he left the Klan in the 40s), and I'd be willing to bet that at the height of the 50s/60s Klan, it was similar to the older national Klan where in some areas it really was a social club for people to make connections in because enough prominent people were members or supporters (like Senator Byrd). Yes, these people were without a doubt racists and spent their time listening to the kleagle rant about uppity niggers, but they didn't join the Klan because they wanted to kill niggers. Even today people who join the Klan join for the same edgy shit because it makes them "real redneckz" or whatever. Antifa is the exact same. You have people who buy the cause and want connections (probably musicians and other artsy types), you have people in Antifa for the edginess of it, and you have people who are hardcore dedicated "kill cops loot businesses".
And let's get real, this is the same sort of shit here. Each and every one of them is complicit with the most violent of them, and yes I'm borrowing their language. The edgy teen in black shouting "fuck da police" is helping the violent thug in black next to him throw firecrackers at people. I'm not saying arrest all these people or that all of them are equal threats, but let's be real, there needs to be a message sent to people like this somehow. The same way to any terrorist group of any belief.