https://www.urbandictionary.com/define.php?term=tankie
not that UD is some kind of godly authority, but in my experience this is the common historical meaning, specifically in contrast of other communists. if ppl use it to deride all communists, i can't speak to that, but it would not be accurate. as i've said, i associate with non-tankie and former tankie Commies.
you never acknowledge this and prefer to wash it all away by claiming it's an empty slur against all Commies, which is pretty divorced from the overarching context.
re: authoritarian states
you didn't prove it, you made a claim and presented evidence.
i am not yet convinced of your (Marxist) claim that "all states are elements of class oppression, and that whichever class controls the state oppresses the rest."
if i were anti-communist, i'd just tell you. but you are correct that i am not communist, nor socialist. not yet at least, mostly due to tankies. we've had this discussion before, i don't particularly want to drag this on.
re: practice
then why not learn from the failings of the USSR, DPRK, PRC in their human rights violations? that would make we take your position more to heart, because when you can't do that, it makes everything else you say empty, because you remain inhuman in your willingness to oppress others.
red boots, blue boots, still boots.