A good leader must be able to inspire action in the people that they lead. Negan and Rick both are able to inspire the people in their communities.
Negan has inspired a cult-like devotion in the Saviors. They act out of a desire to gain position with Negan and to protect him. The slogan that they are all Negan gives them purpose and motivates them to act on behalf of their dictator.
Rick doesn’t ask his followers to protect him or expect them to act on his behalf. There is no code of conduct that he demands they follow. Negan does have a strict code of conduct and he requires all of the Saviors to live by it.
Rick inspires the people at Alexandria to act out of a sense of community and belonging. Rick goes out of way to include each member of the community and make them feel like they are important. The survivors in Alexandria act because they are following Rick’s example. Rick never asks them to do something that he wouldn’t be willing to do.
Because Rick motivates people by appealing to their sense of morality as well as their desire to contribute to the group he wins when it comes to inspiring action.