Those things have existed with or without religion. Yes, maybe religion may have made those crimes more common, but things such as slavery and genocide have happened without religion in mind too.

The first codification of slavery, the Code of Hammurabi, was written by "a righteous man who feared god" Anu, the SkyFather, and Bel, also a god, inspired the Code. The first codification of slavery had divine inspiration. Prior to The Code of Hammurabi, the Sumerian kings would send bands of men to raid neighboring city-states and acquire slaves. As justification Sumer kings would claim that their gods would grant them victory over an inferior people. The first history and writings of slavery were divinely inspired. Religious justification for enslavement has stretched back millennia.

The first genocides were also divinely inspired. From the Melos during the Peloponnesian wars to the Midianites in the Old Testament. The destruction of Carthage was also divinely inspired, over an inferior people. While I do stand corrected that not all genocides (the Soviet genocides specifically) were not carried out in the name of religion. The vast majority and the groundwork for the concept was attributed to divine will.

A good atheist admits his mistakes. I did make too broad of a generalization.

The institution of slavery and the framework for the conducting of genocide were both divinely inspired by the Sky Daddy concepts of the ancient and even modern world. It is easier to convince people to commit atrocities in the name of divine absurdities. Once other rulers saw the effectiveness of divine proclamation it was continued for millennia to justify slavery and genocide. ( If you don't do as I say, you will make the sky papa made, and you don't want to upset sky papa)

The one I expected.

yes

I hear ya brother.

True enough. But if there is a hell, then there has to be an exceptionally nightmarish and horrifying corner of it reserved for those who traffick or purchase children.