Propaganda doesn't work that way, and brainwashing does not exist. I recommend reading Masses, Elites, and Rebels: The Theory of "Brainwashing" when you've got a spare hour.

Either way, I support states controlled by the working classes, which sounds to be authoritarian by your view. In that sense, all Marxists are authoritarian, so I again assert that "tankie" is just a pejorative for communist. The problem I see is that too many people fall for Red Scare propagandizing, and are allergic to contextualization, preferring to analyze everything metaphysically, ie in the abstract, rather than dialectically, ie within its real, existing context. That's why dialectical materialism is so useful.

Authoritarianism is using power, whether military, economic, influence, etc. to dictate the status quo.

So anarchists defending the existence of their commune would be authoritarian