Peter the Rock

Regarding RC apologetics about Peter being the first pope, I wrote:

"'You are Peter, and on this rock I will build my Church' means that Peter can infallibly determine doctrine, he can dispense indulgences, and only those who are in fellowship with his direct successors can do this."

The RC (Who is a good guy, BTW) replied:

"Oh heck. This is too easy. So, you are saying that the entire doctrine of papal infallibility is a conclusion based on a low-probability meaning of this passage alone? There are no other supporting factors in the Catholic argument. It's this or nothing. ..."

Well, on Catholic Answers I found 17 "proofs" of Peter's origins as pope. Of the 17, 12 were direct citations of Matt 16:18, or direct allusions to it. So, I think it is fair to say that the RCC bases its interpretation of Matt 16:18 on a low probability meaning of the passage, because popes have all these powers, e.g. releasing peple from purgatory, anything which proves Petrer was pope means he has these powers. Hence, in RC apologetics (and the link I provided to Catholic Answers has a nihil obstat and an imprimature, it is pretty close to a done deal)it is indeed true that "You are Peter" really means he has the power of indulgences. It is this kind of thing, reading back onto a passage, whether of the Bible, or the Fathers, or anyone also, which I find objectionable in the way apologetics is done. Nothing is ever as it seems, I suppose.