Let's clarify. You said...
"The Church of Christ, broadly considered is the Body of Christ, the called out, "Ecclesia." It is the Kingdom of God on Earth. Like all kingdoms..."
It is NOT the kingdom of God on earth or Jesus would have said so. And His kingdom is not the same as just any ole earthly kingdom. There is no prime minister or it would have been made abundantly clear. Jesus left us the Holy Spirit, pastors, teachers, deacons, elders, overseers...you get the idea. There's not a stitch of scripture anywhere that says a thing about popes or infallible magesteriums.