Replying to How realistic would is the purge?

So I just got done watching the Purge with some friends and after we were talking about just how realistic would the purge be.

My theory is that humans aren't inherently good or evil, but rather we are shaped by society. So if society said that for the next 12 hours all crime was legal and we were told as a society that it's good for us and benefits us then we will respond accordingly and we would support the purge. This is evident in everything from the Gladitiors to people hoping that someone gets knocked out in the UFC, and trophy hunting.

Where as my friends disagreed and said that Humans wouldn't kill another human for the sake of killing and that we as society have compassion for other humans.

Anyways gimmie your theories on just how realistic the purge is.