It is pretty flawed to think about a solution to this with current conditions. We are nowhere near a revolutionary stage. If an Anachist revolution were to happen at some point, what would be done about reactionaries? If they wanted to impose their view on the by then majority of the people through force, they would meet violent resistance. That is in no way authoritarian. Shooting people that shoot at you is perfectly fine. But do you really think reactionary views could gain any support in an Anachist society through non violent means? I don't think a purge where we go around the streets with lists of names would be neccessary. Treat the chuds like the rest: Give them food, shelter and a job if possible, if they still turn violent, use violence. There is no system for them to usurp, no state to coup and it would be hard to persuade anyone about the evil immigrant or big conspiracies in a stateless and borderless society.
If a revolution were to occur, it would be a popular one. If its anachist in nature I would support Anachy, if the MLs are staging one I would support them. Both systems are better than the current one and the fall of the Soviet Union is, as tragic as it was, proof that socialist states can be dismantlt without a further violent uprising. That makes them far less authoritarian than a liberal democracy, even if the state does not wither by itself. But right now we are too far from either possibility for me to pick the most likely candidate to throw my full weight behind, both approaches have some merit in my eyes... Shit, does that make me a centrist?