Communism is both a mode of production, and a process. Socialist countries run by communist parties are properly communist in that they are building communism in the real world. This is why Marx states in The German Ideology that

Communism is for us not a state of affairs which is to be established, an ideal to which reality [will] have to adjust itself. We call communism the real movement which abolishes the present state of things. The conditions of this movement result from the premises now in existence.

The point isn’t that socialist countries would be in that higher mode of production if they weren’t under siege, or that they aren’t sufficiently communist, but that they must build up state power to resist this siege, and as a consequence this state power sometimes commits excesses and mistakes.