I know this is lame for my first post
Been reading for awhile and finally got motivated.
A) I'm not convinced of said "proof". It's been a LA witch hunt for years, and he retires and the focus turns to the rest of the peloton and they start dropping like flies. Riders clean with Armstrong caught down the road can be interpreted for or against, I lean toward the latter because I think if they learned to beat the tests with Lance they'd continue to do so (he is, right?)
B) Lance, at least earlier in his career (and his first book, I think) used to choose his words carefully, at least initially, about doping before cancer (stuff like "I don't use or would not consider using" - present tense - rather than "I've never used"). Suspicious, and lines up with other "hearsay" comments.
C) I tend to believe Lance when he says "after cancer, I can't imagine putting anything foreign into my body". That said, nearly quitting altogether and then soon dominating the TdF is suspicious. Even if he didn't dope before, that temptation had to be huge because what else could he do?
D) Let's entertain the idea he doped before and after cancer. Fast forward a few years when he is a giant name in the US and a hero to cancer patients. That is A LOT to risk continuing to dope, and yet continuing to win would be an argument supporting he didn't dope.
E) No other athlete, to my knowledge, has been so relentless in pursuing allegations against him, not even close along with being the most tested. That would take an ego of massive proportions, which is not impossible for some athletes. But after his 3rd title, I just can't see him justifying that risk to his legacy in any shape or form. It would be maybe the biggest scandal and hippocracy in sports ever, at least in the US. I don't think even Lance's ego is that big for such a risk. I think that's a huge point that doesn't seem to be considered at all by his critics.
So, in conclusion, I tend to attach a pretty high probability that Lance doped before cancer, and quite possibly in his first two or three TdF wins. I think he does care about his legacy and his cause, and I just can't see him continuing to dope in those latter wins or this year. And if you believe he was clean in those, then it casts more than reasonable doubt on him being dirty those first few wins. Although I'll admit a decent argument can be made that he doped as a crutch his first year or two back because else his career may have been over.