Can’t argue with THAT logic! (Of course, the same can be said about every person on earth. Maybe the late Pope John Paul II was on performance-enhancing substances! Just because he never TESTED positive...)
One point from Armstrong’s interview on the Rome show: he said (paraphrasing), "Test my blood; test my urine; hell, keep the samples for 5, 10, 25 years and THEN test ’em. I’m clean."
He also made the point that, after facing near-death due to cancer, he would never jeopardize his health just to gain an athletic edge. Flat out not worth it.
Until proven otherwise, I believe him.