Those who think this was okay are all ignoring ACs own admission it was wrong. First he said he didn't know it had happened (implying he would have waited), then when that was proven an obvious lie, he apologized in YouTube, again on Spanish TV, and again to Schleck himself.
You can list every argument in the world you have that YOU think it's okay, but you'll have to address those arguments to Contador who thinks it was wrong and apologized multiple times for it.
The problem is that, even though he confessed it was wrong, he's going to keep the jersey and the 39 seconds, sort of like "I'm sorry I broke in to your house and stole your TV, would you like to come over and watch it?"
"Hey, mom, I beat some guy's chain to the finish line!" Nice.