Joan75 - Communism has indeed been responsible for the deaths of approximately 100,000,000 deaths in the 20th century.
A disbelief in God is a premise of Marxism.
However your simplistic connection between disbelief in God and mass murder is facile.
Saying that a person does not believe in god tells us almost nothing about them. It's as empty of significance as noticing that somebody has red hair.
Personally I stand for many positive beliefs in humanism and secular ethics. Marxism is a flawed philosophy. Only ignorant youths and ideologues still pay heed to him.
Society has achieved progress standing on the shoulders of men like David Hume, Baruch Spinoza, John Locke and John Stuart Mill. The Enlightenment taught us to reject authoritarianism, whether religious or otherwise.
The sort of fundamentalism that you represent hypocritically enjoys all the benefits of the Enlightenment while trampling on all it stands for.