To be historically accurate you should say “Atrocities committed by the Soviets.” How many atrocities have the leftist in Norway, Sweden or Denmark committed since 1945.
You should call for what is was the Communist Party of the USSR. That is historically accurate, not right leaning propaganda.
I can concede your point partially, that in addition to leftists who commit atrocities, there are leftists who merely enable the mass murderers to gain power, naive of their intentions. There were those in the Kerensky faction that were overjoyed that now that the Communists were in power, they would now be able to abolish capital punishment in the new Soviet Union!
However, you seem to have forgotten about China, Cambodia, North Korea, Cuba, the African Marxist regimes, East Germany, Vietnam, basically the majority of leftist regimes that were murderous nightmares.