This article will explain why this is such an important rule for both the black bears and humans.
Black bears have a natural fear of man.
They are very shy and frightened by humans. Most simply run away when they see or hear humans in their area. Bears can lose this fear of humans when they learn that humans are a source of food. Some campgrounds in the past have had open garbage dumps nearby. Bears quickly learn that this is an easy source of food and begin to lose their natural fear of man.