Russia is only critically supported by communists for its objective material opposition to the current imperialist hegemony by the US. The idea that communists can only support communists is a bit reductive, communists support the international working classes and their liberation. This means supporting elements that weaken the primary world contradiction right now, US imperialism. Obviously communists would prefer Russia turn socialist, but that does not change that it is still playing a progressive role in undermining the US.