If the Christian God existed, why exactly would he allow His church and religion to become so corrupt?

If God really existed, why wouldn't he simply let humans know? God being omnipotent, he could simply convince everyone he existed, instantly. So why the childish games.

If the Christian God really existed, why would He allow all these competing religions to exist? Surely they only serve to send people to Hell - surely a compassionate and loving God would want to avoid torturing people with infinite pain for eternity?