Yes, Marx and Lenin were atheists! Do you know what else? Buddha was a Buddhist. Martin Luther King was a Christian. Malcom X was a Muslim. Great men are great regardless of their religious convictions. Your attempts to slenderize Marx and Lenin for being atheists are wholly baseless. Were they wrong for being atheists? I believe so, but their criticism of religion was not unfounded.
What has “christian charity” done to lift broadly, the toiling masses out of extreme poverty? What has mindfulness done to improve the material conditions of the poor? They are not wrong in their criticism, if anything, they were atheists out of love for working people, out of their desire for the complete freedom of working people. And yes, I say that as both a Christian and a communist. That is your first mistake.
Your second is the ignorant accusation that atheism implies immorality and malevolence. I am friends with many atheists, some of the best, most loving, most dedicated, most compassionate and inspiring people I know happen to be atheists. Religious belief is absolutely no indication whatsoever of a persons ability to feel empathy and to be a decent person and an implication of such indicates a lack of empathy, something that is, to put it bluntly, inhuman.