You're looking for reason and consistency where there is none.
Why do US right wingers who go on and on about "core American values" and the bible cozy up to Nazis and Russia? Obviously those things have literally nothing to do with core American values and the "good old days", in those days large parts of the population took part in WWII killing Nazis and the cold war was still going on. Paying any mind to anything they say is absolutely useless, what they do is what really tells the story. They just want to get their way and the power to punish those who they dislike and those who do things they don't want.
Tankies really aren't any different. They might say they are communists because they eventually want a utopia for all or whatever but what they do is cozy up to hardcore inhumane regimes like China and Russia because it's never been about creating a better world and doing what's right, it's just about furthering and protecting their ideology.