Pretty weird for a black bear to attack a human. Maybe the bears are just getting fed up with getting the short end of the stick in human/bear interactions. The bears finally realized that they are faster, stronger, and already knew they aren't picky about what they eat, and there are just so dang many people. Everywhere a bear goes, there's more people. Maybe they're just trying to make the best of the situation and take advantage of the abundance of slow, weak, and generally fat humans. Optimal foraging theory taken to the next level.

Sg