I think we are completely agreed that all churches are imperfect representations of the Kingdom of God. As a Protestant who has spent most of his adult life in the contested borderlands between Evangelicalism and mainline Progressive Protestantism, I can see strength in each movement.
What is interesting to me is how many denominations begin with a claim of higher morality or faithfulness to God. If Martin Luther hadn’t rejected Catholicism and the authority of the Pope, Lutheranism might never have emerged. If Abraham had never left his father’s house, would Judaism, Christianity, and Islam have been born. The Apostles all chose following Jesus over the traditions of Judaism. I wonder if God calls some people to leave and others to stay.
I wrote my undergraduate thesis on varieties of resistance to Soviet Communism in the Russian Orthodox Church. When official repression of the Church ended in 1988 it was extremely difficult for groups that had “compromised” with the state and those who had “resisted” state control to be reunited. There was too much bad blood between each side.
It was not dissimilar to the Separatist Puritans who founded Plymouth Colony, and the non-separatists who founded Massachusetts Bay. One thought they had to leave to faithfully follow God, the other believed they could reform the institution from within.
I am trying to do what makes sense to me and not judge those who make other decisions. That is not an easy task.
Peace.