Lance Armstrong does not feel guilty. He probably feels considerably more cheated than the people who are whining over the old news / incredibly obvious fact that he used PEDs during an era where nearly everybody was doped to the gills. EVERYBODY in the know knew that he was doping, that his competitors were doping, but nobody cared enough to do anything about it because they (the fans, the sponsors, the federation) benefited just as much from it as Lance did. It was only when the federation realized it needed to solve its credibility crisis by exposing the big man that they finally decided to crucify him.
Sure, there were some who resistend and were pushed out of the sport, but it was a massive institutional problem, and blaming it on one person is naive. You wonder why nobody's stepping forward to claim Lance's TDF wins? Because the athletes know that he was the best; nobody is ever going to dispute that. The fact that Lance is also a total ass hole makes it easy to hate him and make him the scapegoat for an entire era. If he was a nicer guy and made the right moves earlier, he probably could have come out of all this relatively unscathed, even heroic. But the fact is that he was just the best bike doper in the sport of bike doping, and I, for one, loved watching him race.