The only way that it's common sense that Lance Armstrong doped is if it's also common sense that all elite cyclists dope. And if that's the case, why should we care that he doped, too? There was no uneven playing field.
I'm not saying I don't think Lance Armstrong doped. I don't honestly care, and I'm well aware of the mountains of evidence suggesting he did. My issue is that if it's unfathomable that someone could dominate without doping, then it must be true that everyone dopes. And if everyone dopes, again, who cares that this guy did? He was following protocol for his sport.