I've seen communists of every denomination get called tankies. I've seen progressive liberals get called tankies by zionists for supporting Palestine. I've seen anarchists get called tankies by liberals for saying the Uighur genocide is not real. I'm pretty sure I once saw a conservative get called a tankie by other conservatives for not being far right enough, but I can't say I remember where.

My point is, it's really not helpful to act like the word "tankie" actually has some agreed-upon meaning. If you're generally on the left, some group of people out there will consider you a tankie. I guarantee that, it's just a matter of waiting and seeing.

If you want to say that there are communists who are authoritarian and there are communists who aren't say that instead, and we can have another conversation.

"Tankie" is just a pejorative for communists, it's a strawman that essentially says that the Red Scare was correct, but that that's a good thing. In reality, the ones called "tankies" have very reasonable views and reasons for supporting existing socialism, the label gets thrown to shut down discussion.