Religion, at least according to the Bible, has no problem with rape, incest, and slavery. I favor the kind of non-religious morality that frowns on those things.

In any case, these dictators were not motivated in any way by their atheism. Their atheism didn't enter into the equation and as you pointed out, they represent a tiny fraction of atheists worldwide.

And it could be pointed out that there has been lots of evil done in the name of religion, such as the Albigensian Massacre which was a military and ideological campaign initiated by Pope Innocent III against the Cathars in France. And Hitler was a Xian; the German Werhmacht (Nazi military) wore belt buckles reading “Gott mit uns” meaning God is with us on their belt buckles.

It's a much better form of morality because it is done without any promise of a reward in heaven or threat of punishment in hell, since both of those places only exist in the imaginations of credulous people.

The idea that atheists are somehow less moral than believers is incorrect and downright stupid. There is absolutely no data to support the idea that atheists as a group are any less moral than any other randomly chosen group of people. In fact, just the opposite is true; for example, atheists are much less likely to wind up in jail.

It's a sad fact that people who hold these silly beliefs never stop and ask themselves if they have any data or facts to support those beliefs. Believers tend not to ever question their beliefs.