You must have my response mixed up with someone else's. I don't believe the two passages contradict one another, and I said so. Jesus was not forbidding public prayer-- he was forbidding public prayer for the sake of drawing attention to one's own piety. If Jesus was forbidding public prayer, the Church could not get together to pray corporately, as it clearly did at times in the Book of Acts.
I guess we disagree on what prayer is. To me, prayer is communicating with God, whether it is giving thanks, making a request, or confessing sin. In my view, petition is an important form of prayer, but not the only one.