As far as them "eating us"....they aren't carnivores, as a general rule. Black bears prefer berries and acorns and get most of their protein from eating grubs in hollow logs or under rocks.
Black bears have been known to eat meat if their food supply is dwindling and they find a mountain lion kill, but that's pretty rare. They "ARE" opportunists.
But a Grizzlie or Polar Bear would not only kill you, but have you for supper, too.
That is a false hood put out by the anti's black bear reagularly eat meat. They prey on the elk and deer fawns all the time. They well eat anything they can catch.