Ahhhhh.....I see.
So if we can find a church where there is absolutely no corruption, this would indicate the absence of any false doctrine.....ergo, we've found the one, true Church.
Have I got that right?
Nope. Humans are fallible. Good Biblically-based doctrine merely mitigates the corruption that is inherent in all of us. But when people are told to pray to Mary and other humans, that doing good works will save them and that they should treat the mumblings of scared children in the same manner as Holy Scripture, the very foundation of that faith is false and corruption will run rampant as the whole world has seen in the Catholic Church.