-
He'd crashed and was trying to get back to the front group. It was blatant and caught on camera hence the disqualification. But if he'd been getting the magic spanner treatment whilst they gradually towed him back up, no one would've complained.
There's also the fact that he was not driving the car, so the ds who decided that was the right course of action should bear most of the responsibility.
To be fair to Nibali, he was only doing what pretty much every other pro rider has done, it's just he got caught on camera.
I don't see everyone bellyaching when riders get the magic spanner or sticky bidon treatment.