Carols said:
I think Greg Lemond's explanation was perfectly sensible. Indeed, he said he had done the same himself: You think you will have to quit. You don't want to. You give yourself one more test, to see, if by some miracle, it turns out you are better than you think. It turns out you are not (no surprise really), so you finally (reluctantly) have to accept that the best thing to do is to admit defeat and abandon the race. I also happen to think that Contador would want to go out trying - for himself, his view of himself, for his sponsors and his fans.
What LeMond says might be. Truth is, he knows same nothing as armchair players, it's just speculation, too. At the end it boils down to what you want or what you don't want to believe (or you may stay say neutral a consider both options possible).
I only wonder why did he not simply wait for stage itself to test him? It wasn't really necesessary to test himself this, by going on attack. He could just stay there and wait till real test comes and untill than he could eventually get better (or worse, of course).