He lost his lead out man, tucked in behind the Veelers and Kittel. Once Veelers has done his job he should get out of the way. What actually happens is he turns around, sees Cav and lets himself drift that way to block him. Cavendish gives what he gets. Racing.
What an utter pile of shite, neither one of them did anything deliberately.
Watch the video, he is pretty buggered after doing his turn, moves a bit left, then slowly moves a bit right. It just unfortunate that he moved into the path cav was taking to get on the wheel in front.
Once the lead out man has done his job, he either swings well out off the way, or if he cant, he should hold a straight line because he knows sprinters will/could be coming either side of him. Watching where he is relative to the white line, you see can see that he goes one way then drifts the other way.
As cav demonstrated, you dont want to get in the way of a sprinter coming from behind you, hence the reason you keep going as straight as possible when you have done your turn.
Try it yourself, go out and give everything you have for 30-60 seconds and then see how straight a line you can hold when you’re finished.