I don't believe this is where cultural relativism contradicts itself because it doesn't necessarily say that every cultural action or belief should be accepted. Cultural relativism more so just encourages people to understand that everyone has different practices then others inside their cultures. Even Newrepublic says "ethical standards are universal". I put that quote from that article just to say all cultures have a different belief on what's right and wrong. With this being said I still fully stand with you that in the cases of mass murder, slavery, and racism in a culture are intolerable.
