We disagree on that. All the people in the world will prove you wrong, they are all sinners. You have it precisely backwards. Self interest is the reason people do wrong.
They don't behave themselves and do "right". And we have the inevitable chaos.
Sure they will! All you have to do is appeal to their reason, and point out how not acting like a barbarian will give them better returns than making themselves an outcast from other, more civilized folks. Appeal to their greed, if nothing else. That often works...and that's what I mean by self-interest.
With a screenname like yours, I guess I ought not be surprised that you like to argue. :)