Some spoilers lay ahead.
If Negan is a classic psychopath who rules by fear and intimidation, Ezekiel runs the Kingdom through charisma, competence, and more than a little playacting. Ezekiel was a zoo keeper before the zombie outbreak, hence the tiger who growls beside him as he sits on his throne. But he also did Shakespeare in community theater and had based his leadership style on the best of England’s kings as depicted by the Bard.
To be sure every great leader is a actor. John F. Kennedy pretended to be all youth and vigor to bring about a new frontier while he was wracked with pain from a back injury and Addison’s Disease. Ronald Reagan, an actual actor, playing the hero president who brought his country out of the malaise of the 1970s to win the Cold War.
Ezekiel has created a community that is a little bit of Camelot and a little bit of RenFaire. He has his knights who ride around on horseback who fight zombies and protects the community.
But the playacting is just the costume that gussies up a competent, compassionate leader who wants what is best for his people. The people of the Kingdom eat well and live in relative safety. Ezekiel even knows when to lie, especially about the arrangement he has made with the Saviors to give them pigs as their tribute, though fed with zombie meat.
Ezekiel is not insane. He knows that he is not King Henry V come back to life. He admits to Carol what he is and what he is doing. But his persona has provided hope and cohesion to a community of people who have been cut adrift from their old lives by the zombie apocalypse. Who knows? Perhaps King Arthur knew he was just a Romano-Celtic warlord trying to keep things together after the fall of Rome. When faced with a choice between reality and the legend, always print the legend. The two have a tendency to become one after a while.