Would there even be Nazism, if there wasn’t Soviet Union? Would Eastern Europe swapped so easy if there would be Ukraine and other countries there?
All these arguments are too much “what if” to justify Russian Empire in Red paint, that organized its own genocides at that time. And yes, Western Communist Parties are not the same. But being Communist in that time meant was to give your autonomy and life to the interests of Moscow. Especially in 1930s, during the period of “Bolshevization of Communist Parties” as it is known in historiography.
Many CP members all over the world were killed by the USSR’s secret police, with the most appaling cleansings being in Spain; with Communist Parties de-facto supporting peace with Nazi Germany and collaboration from 1939 to 1941, and then in 1945 statements by Thorez (PCF head) and Togliatti (PCdI) that they won’t defend their countries if Soviet Union would decide to invade, but will help Russia.