The Amish are only able to hold together without the threat of violence because they dump the responsibility on others. Small, tightly-knit group of people always have an ultimate solution to cases they can't handle : expulsion. These groups will typically use several methods to enforce their rules. Usually it starts with reason (convince people through logic), then shaming (for your Amish example above, that would be the forced beard-cutting and such) and finally when those fail, they expel the offending member from the community. To keep with your Amish example, when a violent offender becomes too much to handle for them, say a serial rapist or murderer, they call outside authorities to deal with them.
Let's pretend that this option wasn't available because the whole world is Amish. What happens when a few pariahs get together and go down the path of banditry? They'll steal and rape and pillage their ways until someone uses violence to stop them. So you start needing people to deal with those cases. So now you need a police force, etc...
To come back to your original statement, you're right that evolution applies to societies in general. The societies with the best set or rules (laws & ideology) will tend to prosper and others will fail. However, the willingness to use violence is the most basic component of every society. If tomorrow, somebody convinces half the people of a country that murder is right, the only option for the other half is to defend themselves. Sure, you can try to convince people through reason, but if that fails, violence is the only last resort that works. If you forgo violence and someone is willing to use it against you, you'll die, and all your nice ideologies about rights and peace and whatnot will go with you.