I think the term does not mean what it meant a long time ago as even the Wikipedia article states that there’s already like 7 definitions of it. The original definition is not even related to the Tank Man which is its most popular reference these days.

After the Prague Spring, the term was used to describe Communist party members of Western countries who had supported the invasion of Czechoslovakia

I see no reason to for the arbitrary limitation to only call Communists Tankies as we could also start a semantics discussion that China and Russia aren’t exactly communist countries anymore.