Could thousands of years of repressing animal instincts lead to social de-evolution?

you are correct, we are just a bunch of walking time bombs, Carl Jung to said so, that we are repressing are primate state, but eventually it is released and not always in good ways. but we cant just let people do whatever, we still need some ethical codes to live by, we are suppose to be more evolved, therefore not just act like a bunch of.... well... apes.