Kings of these worlds had their own ways and they acted more like dictators. There are only a very few countries in the world which continue the monarchy system, and most countries have adopted the democratic method of choosing a leader among the masses to lead them. However, these leaders who are elected through the democratic processes act worse than the Kings and impose their dictatorship on the people who elected them.
A leader should be a person who leads by example. An example (not sure if it is real though) drawn from the life of Mahatma Gandhi is that a lady from a far away village came to him seeking advice on how to control her kid who is always hyper active which leads to naughtiness. Mahatma Gandhi knew the solution for it, but asked the lady to go home and return in a month so that he can tell her a solution for the problem. When the lady returns after a month, Gandhi suggests to the lady that she doesn't give sweets to the kid. When the lady asked why he did not tell this the last time itself, he replied that it took him a month to give up sweets so that he can tell her to stop giving sweets to her kid with no guilt.
Jesus Christ is a real leader. He went through many hardships and went to the extent of sacrificing his life for our sins. He lead by example, but he doesn't demand us to live exactly the same way he did. As Catholics, we are asked to live in a measure of what he did. Jesus is not a dictator kind of King. He is democratic - he blesses us with the health and wealth, and we are asked to serve him through the less fortunate with the blessings that he has bestowed upon us.