I don’t think it’s been confirmed that these people are left wing authoritarians. It also seems like a dangerous way to think about this as a problem rationally. You’re basically deciding the facts of the matter outside of any actual evidence or argument.

Further writing people off sounds pretty authoritarian.

I regret making such a sweeping statement. I do think there are many decent people that get caught up in the cancel mob who are primarily motivated by genuine egalitarianism, and these people can surely be reasoned with.

However, at the same time I do believe that some (perhaps a small minority) of the agitators are cynically motivated by narcissism and sadism, and there's quite a bit of research which points in this direction. For example, the close connection between virtue signalling and grandiose narcissism. Reasoning with this particular subset (however small they may be) is probably not going to be productive because their actions aren't coming from a place of real egalitarianism.

That's the problem people on all colors of the political spectrum, followers are influenced by minorities with too much rage and anger. Sometimes this rage and anger comes from an important societal issue, but that's not an excuse for shitty behavior you wouldn't like the another political opinonated mob to use.