I don't think he "knows" that. I'm guessing HH has a different opinion... Cav had been sprinting for a lot longer and was running out of juice. It would have been photo-finish material, but I think HH would have taken it.
It looks pretty clear to me. Cav was running out of gas and he swept HH before the line. HH didn't move out of his way, and they crashed. You can't blame HH for riding straight. This is 100% on Cavendish. Let's face it, he's not used to guys coming up on him in a sprint, so he doesn't quite have the "subtle sweep" down like a lot of guys. Even if HH had moved wildly to his left to avoid the crash, Cav would have been DQ'd. That happens when you put guys into the barriers on EACH side of the road in the same 200 meters....
I didn't see any malevolence, just bad sprinting.