Hmm, I don't know if you can say that categorically.

My understanding is that it's very, extremely rare for a blackie or a griz to attack a human with predatory (as opposed to defensive) intent. But it is not unknown. A young or desperate or starving bear may sieze any opportunity that presents itself. The fact that we humans have modified head-parts and a rather good opinion of ourselves doesn't diminish our caloric value.

As to corpses, animal or human-animal, I believe bears will indeed scavenge if need be. Again, it's nothing more than a free meal in a tough landscape.