They're really not. Grizzlies are just inland brown bears. They mostly want to eat berries, salmon, roots, and whatever else they can find. They don't want to bother people. Males aren't really territorial about humans and females with cubs want to protect the cubs, not fight you. If you respect their space by making plenty of noise so they know you're coming and stay away from their babies and food they'll mostly leave you alone. They are extremely dangerous, but attacks are rare and often happen when the victim made an identifiable mistake - Approaching the bear, keeping food in their tent, traveling alone. There is a risk of bear attack, but the risk can be greatly mitigated with good bear safety practices.