I don't think your second paragraph follows from the first. The cited revolts were largely fascist in origin, for example the Hungarian revolt had the fascists lynching Soviet Officials and freeing Nazis from prison in order to assist with lynching Soviet Officials. Calling them "dissidents" or pretending they were ethnic minorities is ridiculous. Not answering fascists lynchings with violence would be incredibly terrible.

The "rebels" were trained and supplied by MI6, and had marked the doors of Jews and Communists for extermination.

Really curious what a "non-tankie" would recommend doing in such a situation. Giving the Nazis that killed hundreds of people flowers?

I've always thought of them as the communists who think communists are somehow uniquely immune to the "power corrupts" doctrine

Authoritarian communist, essentially

Wikipedia has a good article about the term

That would probably be some ultras, they are very desperate to be recognized by liberals as "true communists" unlike those "fake authoritarians". Liberals of course don't give a shit and immediately labeled ultras as tankies as well.

Why do the anti-authoritarians not confine themselves to crying out against political authority, the state? All Socialists are agreed that the political state, and with it political authority, will disappear as a result of the coming social revolution, that is, that public functions will lose their political character and will be transformed into the simple administrative functions of watching over the true interests of society. But the anti-authoritarians demand that the political state be abolished at one stroke, even before the social conditions that gave birth to it have been destroyed. They demand that the first act of the social revolution shall be the abolition of authority. Have these gentlemen ever seen a revolution? A revolution is certainly the most authoritarian thing there is; it is the act whereby one part of the population imposes its will upon the other part by means of rifles, bayonets and cannon — authoritarian means, if such there be at all; and if the victorious party does not want to have fought in vain, it must maintain this rule by means of the terror which its arms inspire in the reactionists. Would the Paris Commune have lasted a single day if it had not made use of this authority of the armed people against the bourgeois? Should we not, on the contrary, reproach it for not having used it freely enough?

On authority, by Frederick Engels 1872

https://www.marxists.org/archive/marx/works/1872/10/authority.htm

Not really, no. To a capitalist, all forms of leftism is 'authoritarian,' because they consider private property natural and oppose leftists 'stealing' in.

'Authoritarianism' just isn't a particularly useful term because nobody who uses is is ever actually categorically opposed to forcefully compelling people to do or not do things. They will always have a build in exception for what ever they consider to be 'legitimate authority', and what they consider justified authority will just depend on what political philosophy they ascribe to. So really calling the word just means "someone with a different political theory to me with regards to legitimate authority."