When I said every atrocity can be retraced to divine vindication I excluded those perpetrated by pseudo-religious systems like Maoism or Kim-Jong-Illness. But the mechanisms are basically the same. Like in religion there is (mostly economic but also social) rigid dogma that overrules rationalism and pragmatism to perpetuate the power structures.

There is a major difference between totalitarian atheism which is just an instrument to supplant the strong religious bonds by putting the state or a dear (divine) leader in their place, often even potentiating them and personal (philosophical) atheism which is just a lack of belief in gods and has not an agenda in itself and is not automatically replaced by something else.

I will not take a bet, but I doubt that there were many crimes committed in the name of atheism where it was not an excuse (apart from lone mad men). You can say that for religion to some extent but there were clearly many instances where the religious memes are not just used as subterfuges but are themselves responsible for the (then often more gruesome) atrocities, e.g. the Spanish Inquisition, Muslim honor killings, many other quarrels over minor dogmatic discrepancies (the Crusades, maybe, too). They often added to or even induced the cruelty in warfare because all they had to do is to attach spiritual or moral evil to an adversary: all psychological restrictions fell and the enemies could be treated as non-human.

I can't say for certain that oppression or atrocities would decrease if religion suddenly vanishes, but I firmly believe that would be the case. Just look at the stats concerning religiosity and crime, like the religious affiliation of the prison population. And the crime rates in generally less religious countries. Of course those correlations are counteracted by superseding nationalistic, chauvinistic, racial and other tendencies which are IMHO partly responsible for the belligerence of the U.S. as of lately.

I am a little torn on banning religion. Of course I don't advocate dictating what people think and interfering what people do in their homes or even congregations (that latter can be argued about though) but I am certainly against any religous influence in politics and in public in general as well as any kind of special treatment or pleading of religion like tax-exempt status, priests as moral authorities, public repression of women and other groups etc.

I would not call that oppression or infringement of any basic laws or human laws, but assigning to religion the role it deserves: as a petty sideshow.