"For atheism" would only be true if atheism was the singular goal of the perpetrators. It was not. The primary goal was ideologically-based, not religious (or quasi-religious, as your assertion implies). That is an historical fact.<quoted text>
Stalin's murder, and all communist murder, has been for atheism.
It's a historical fact.
I believe your assertion is defensive, attempting to create some kind of equivalency, born in an embarrassed recognition that many historical atrocities have been solidly based with a faith-based goal in mind.