I dont know if 20% of people are insane. But i know how to keep them from toxifying the public sphere : Keep them out of government! Don't vote for them and don't support government organization. If the laws and courts are corrupt - privitize them.
Negan is a lot like the federal government; he wants your guns and half your income. His loyalists patriotism reminds of the blind faith that people put into all organizations that promise to keep you safe while actually victimizing you. They were all capable of choosing cooperation but they chose instead coercive theft. I guess it's the appeal of easy money. They are just bandits. Rick is right to deny their claim to his property.