That is a thing we disagree on. In a sense. I don't really care what word we use. But we agree that Christ is king. We just disagree on what a kingdom looks like. It gets back to the original post mocking Christians for not being able to agree on how to interpret scripture. It is a valid criticism and a scandal. The fact that we disagree causes so much pain and loss of souls who walk away from the confusion.

Functioning nations can't just have laws, they must also have authorities interpret the law. Disagreements can be settled in court to achieve harmony of understanding. Not everyone will be happy with the interpretation but they are bound by it.

Relying on scripture alone is empirically a failure. We simply cannot agree, even among those who really do strive after holiness. God is not an idiot. He knows this and He would not contrive a system that could not work. Do he left an interpretive authority.

"You are Peter and upon this rock I will build my church, I give you the keys of the kingdom, Whatever you loose on earth is loosed in heaven, whatever you hold bound on earth is bound in heaven."

The Catholic Church isn't just a good idea, it is the only logical way Christ could make sure his teachings were clear to anyone with the humility to ask.