1. Tens of thousands of people are part of societies where initiation into the society entails killing someone. (Various gangs).
2. Hundreds of millions of people are living in societies where honor killings is a thing.
3. Depending on how you count, there have been more than twenty genocides in the last century. That's during 0.05% of the time Homo Sapiens have been around.
4. Hundreds of millions (if not billions) of people are living in societies where a blogger can get lynched for a blasphemous post.
5. There have actually been societies in recent times ending up literally poisoning each other.
6. Just some 5 years ago around 10 million people lived in a society where people were thrown off roofs for being gay.
The list is obviously non-exhaustive. And all of the above is basically going on now, I'm not even getting into what we know went on a few centuries from now. Burning innocent women on pyres for imagined slights, anyone?
Like... Do all these people know/knew they are evil according to our 'common' and 'universal' core morals? I bet they feel pretty good about themselves when lynching the blasphemer. It's just that I refuse to accept that our core morals are similar.