Jesus did not say he would build his church on Peter. Peter answered his question, and his answer was what Jesus said he would build his church on. Seriously, do you think God would build his church on an fallible human being, and one who had denied Christ three times? Unbelievable.
Classes in Reading Comprehension for those who believe that.
I think you misunderstood that post you are responding to. I am NOT a Catholic and do NOT believe that Jesus build His ekklesia on a fallible human.