All the "wtf is wrong with people" horror sort of presupposes that, first, other members of the crowd were aware that there was a person being trampled to death and, second, that they did not care, doesn't it? People get trampled because once a crowd gets moving, it's difficult or impossible for individuals in it to stop moving, not because those individuals are so callous that they don't mind killing someone to get to their destination.
It is very much Wal-Mart's fault; THEY are the ones who intentionally whip customers into a frenzy. THEY are the ones who failed to provide adequate security, either by guards or barriers. THEY are the ones who put cheap, crap doors on the store. You call the police for crowd control and don't open the doors until people are compliant.
Best Buy puts up barriers in the store, like a maze, and you have to go through that.
But then again, it's Wal-Mart. They probably get to collect on some dead peasant policy or something.