I think you are confusing antifa with anarchists. Antifa, at least in their roots, are nothing more than anti-fascism. It's a movement born in Europe around the 70s when neo-nazis first dared crawl out of their post-WWII gutters again.
They kinda have nothing to do with anarchists, although admittedly, most angry mobs nowadays that either call themselves antifa or anarchist, or get labelled that by the media, are one and the same, just angry mobs looking for an excuse to riot.
Those groups are linked together for good reasons
Antifas are a branch of anarchists, or at least were considered as such when I was involved in the anarchist movement. From what I can remember, the antifas were the wierd and violent dudes that would infiltrate demonstrations to fight the anti riot police. They do (or did?) consider any form of government as inherently fascist and that was how they would justify going at the police.
They would be somewhat fetishised by the rest because violence is fascinating, so I assume todays youngs are trying to emulate them, but they obviously don't put off the work. Antifas should never get in a situation where they can get caught by the police, let alone engaged by counter protesters
They would not blend in the rest of the crowd, and we know who they were mostly by common relations. But from what I can remember, they were effiscient, and had plans including an escape plan everytime they started something. They would start the violence and get out before it ends
Things really seem to have changed since then, and it wasnt even so long ago.