I won the argument with the simple premise: "Actions speak louder than words". As one of the Twelve, Peter was never "out of the chair", everything he did and said taught morals and doctrine. He was wrong, as this Catholic approved translation says---therefore not infallible:
And when Cephas came to Antioch, I opposed him to his face because he clearly was wrong (Gal. 2:11 NAB)
Peter was just a man, deeply flawed, confused, and hypocritical. Catholics exalt him for no valid reason. Since Jesus called him "Satan", exalting him is beyond crazy!
You two protestants ought to get together and sort out your attitudes to Peter.
For Alfred Persson Peter can do nothing wrong.
For jaybo Peter can do nothing right.
But that is typical of Protestantism; 40,000 denominations, sects, cults and one Pastor churches (+ all the "non-denominational" individuals) all proclaiming contradictory doctrines.