That's for starters. I know that you believe what you are saying. But you're assuming that your (the RCC) interpretation of the verse is true. It's fine to have beliefs and it's good to hold to them staunchly. However, to pretend that it is the only possible interpretation is fanciful. To simply state something with conviction is not a proof.
Christ also told Peter..."whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in Heaven." This here by Jesus himself gives authority to Peter to govern HIS church. Therefore the authority of the one who sits in the chair of Peter is a true authority of God's established Church, since Peter was given the keys to Heaven and his established laws of the Church which are bound in Heaven. GOD DOES NOT LIE AND CAN'T.
Further..St Paul says there is one Christ and one baptism. What he is saying there is ONE FAITH.
Huh?