I agree that it was a surprise to hear him call himself a jerk (I think that was the actual term he used with Oprah) and that was a bright spot in that interview.
And no, he was far from the only one cheating. But when you're at the top you're going to attract more attention (which he was never shy of) and you're going to become a target - the biggest target - when it appears you've done wrong.
Before the allegations began, I was an admirer of his achievements but not of his personality. I remember him as a young pro before his cancer scare and he was brash and arrogant as much as he was talented. Who knows how good he could have been clean (ok, in a clean sport)?
The same can be said for David Millar who was already a big talent before the drugs an lost a lot of momentum after them. But he will be ending his career looking very strong and I feel he would have been a far more consistently high finisher without the drugs scandal.
But that can only ever be conjecture because we never got to see all the world's top cyclists ride clean at the same time in their respective eras.
Ironically, because it seems so many riders were cheating, it actually seems easier to look back at old races and enjoy the spectacle without thinking "that person shouldn't have won" because there's a fair chance nobody else in contention had any more right to win! That's where some people get the twisted notion that drugs should be allowed because it would make for an even playing field though.