I'll break humans into three categories:
Inherently good: People with actual moral systems that they will never break. They are good people not out of fear for consequences, but because they are empathetic people who genuinely want to treat others well. Maybe 8% of the population, I'd say.
Neutral: 90% of the population. No real morality. They'll just do whatever they can get away with... give in to whatever animal instincts they can. If they think they can't get away with something, they won't do it. They're governed by fear basically. If they fear the consequences of their actions, they'll hold back. If that fear is removed, they'll do whatever they want. Mob rule, basically.
Inherently evil: Probably 2% of the population. These are people who have, basically, the inverse of morality. They thrive on other people suffering. That is their goal. Even the worst of dictators aren't like this. Hitler thought that his actions would make the world a better place. He wasn't evil, he was just a fucking idiot.
As for the "inherently" bit. You can argue that forever. I think, in terms of what influences a person's morality, a fair bit of it is "born-in", and a fair bit is conditioned. Some people are just born with way more empathy than your average person. Some people don't need morality explained to them. They just do it. They want to be nice to other people.
If I go by my categories, I'd say that conditioning has the largest effect on the neutral group. They aren't inherently good or evil. Society will tell them how to act. And, I don't think society itself is inherently good or evil. It's self-serving. We promote "good" in our laws (generally) so we don't have to put up with other people killing us and stuff. It's a live and let live(/die) sort of approach. Society doesn't care what you do as long as you don't harm society.
The good and evil groups have, arguably, more or less made up their minds from birth onward. Conditioning won't have as big of an effect on them.
IMO
