We lose a half dozen or so people a year to predatory black bear "encounters". That's when a black bear decides you look like you might taste good and actually stalks you. Most bear encounters are accidental surprising both parties involved.
A few years ago a young male, maybe 250 lbs was investigating my neighbours carport for food and I decided to chase him away. He was nervous looking, not really acclimated to humans, kept nervously looking around, ears flicking up etc. so I decided he wasn't too dangerous. I started running at him yelling and flapping my arms, but he just stood up (they are amazingly tall when they do that) and tried to find out what the hell I was doing. They have really poor vision, depending on smell and hearing mostly. I started getting closer and closer to my "do not cross" line when he finally dropped and ran. Hopefully I taught him humans are really predators, and not prey. That's the two divisions that bears know, you are either one or the other.
It's when idiots that don't know anything about black bears and their body language get cocky and start feeding them to get them to come closer to take better pictures that bears get bolder and more dangerous.
This particular poster is a darkly humerous take off on real ones that are posted mostly in our national parks. It's partly right. Bear bells only scare off bears that are not acclimated to humans, and bear spray works, but again only on "wild" bears. If a black bear really wants you for dinner, a 12 guage with slugs or SSSG is the best answer.
Now Grizzlys are a whole 'nuther story!