Beltaine? Isn't that pretty much Easter? Pretty sure the Celts weren't Satanists.
Communism, Marxism, and Stalinism are different things. Stalinism is a strain of Marxism, and communism is an element of Marxism, but they are all different.
Orthodox Marxism has strains of authoritarianism and classism, and extremists have murdered millions in its name. Heterodox Marxism tends to be quite peaceful and liberal. Communism, on the other hand, is nothing more than the abolition of private property*. It is a purely economic proposition. Communists can be avowed libertarians (Rosa Luxembourg) or extremely authoritarian (Stalin). They can be liberal (Trotsky) or conservative (Lenin). Most anarchists are communists (Emma Goldman, Pyotr Kropotkin). Because of its populist rhetoric and identification of an enemy (capitalist class), communism can be easily used as a tool to manipulate the masses, even if the leader is not actually a communist (Pol Pot). There are also even non-communist Marxists (President Allende of Chile).
In short, please stop confusing these terms. Communists and Marxists are at least as different as Democrats and Republicans... And despite being tempted, I've never conflated those terms.
Communism is no more responsible for those deaths than capitalism is responsible for the mass murders Pinochet, bin Laden and other capitalist authoritarians have committed. It is authoritarianism which commits mass murder, every single time. Marxism-Leninism, and its most foul form Stalinism, allowed the spirit of the Paris Commune to be used to justify atrocities. But that is not what communism is. Even Marx would have rolled in his grave knowing what Stalin did. He meant to be a theorist, not a cult's prophet.
*Property is also used in a different meaning than you're probably used to... It means land, natural resources and the means of production, not personal posessions.