You apparently think that Christ has not the power to keep his Church true to his teachings which makes him a mere man and not God.
Who believes he is not God? Certainly not the true Church, certainly not me. I am not an Arian. Though I am not Trinitarian, I automatically side with Trinitarians - the non-RCC kind - over against the Arians, and any and all who deny Christ's deity.
Just pay attention to historical facts and you get the same result.