I don’t really get what your argument is here. The only reason he’s in the line he’s on is because Crosby bumped him. What do you expect him to do? There’s no time to get out of the way at all.
Can someone answer that question? What is he to do?
Sharp cut to the side? Opens himself up to either taking or giving a nasty knee or ankle injury, and a tripping penalty.
Drop to the ice? Could end up getting cut or breaking Letang's leg. Tripping penalty as well.
Try to turn? Could result in a headshot or high-sticking on Letang, or the opposite coming back.
I think he made the only play he could have: brace for the impact, try to minimize damage as much as he could. Unfortunate result from a strange play. I don't see any malice in the hit, and ultimately don't consider it dirty or even questionable.