The first thing to remember when dealing with any sort of bear is to leave them the H alone. Don’t go for that selfie. Don’t taunt them. Don’t chase them. And above all DO NOT FEED THEM! And keep in mind that with a large grizzly you are not safe in your car or pickup. Most people do not understand how heavy, fast and powerful a large grizzly can be. A grizz can cover a couple hundred yards with a blown out heart. A grizz can outrun a horse.
It is too easy to make generalizations about bears. In the east, black bears are less aggressive and are more used to people. In certain regions of Alaska and British columbia one may encounter the predatory black bear. The last thing you see is a black blur coming out of the woods at the speed of a horse.
People have employed all sorts of ways to deal with bears. I have chased a large grizzly out of the yard banging a pot with a ladle. I have also had to dispatch a grizzly with a rifle.
Grizzlies especially are opportunistic omnivores. So it is very impoprtant to keep a clean house yard or campsite. A grizz may decide that your place is a great den. I had a neighbor who had a grizz tear off the overhead door on his garage, overturn a freezer, and decide that this was a great place to hang out. It was evetually dispatched from an upstairs window with a .300 magnum.
The two most dangerous encounters are cub defense and carcass defense. Never approach a sow with cubs. Never approach a feeding bear. IF you come across a carcass LEAVE THE AREA.
Pepper spray or a pistol can discourage a bear that is only casually interested in you. If you have been identified as a threat or a food source you want to have a large caliber weapon.
I believe you are mistaken. Predatory black bears usually approach with considerable caution. They are uncertain of humans as prey, so they take their time to evaluate the prey and "test" it to be sure it is not dangerous.
They close in on the person like a cat closing in on a bird. People almost always see them coming and have plenty of time to prepare for it, which very often ends with the bear being killed.
Here are cases of two geologists who were stalked by predatory black bears in Alaska. One did not have a gun and was terribly mauled, losing both arms (bears are not quick killers). The other had a gun and killed the bear as it attempted to close with her. She remembered what happened to her colleague.
A properly placed handgun bullet can easily kill even the largest bears.
It has been done many times.
Modern magnum pistol calibers equal or surpass many black powder rifle rounds in power.
These rounds were considered to have more then enough power to hunt large game.