Aggression only works if the animal believes it. The bear was testing her. If she had run, he would have attacked. If she had fought, he might have challenged her since she was about the same size. By just going about her business, she indicated to him that she was ignoring his challenge because she could. That kept him from acting.
Aggression may have scared him off sooner, and that is exactly what I would have done. But she was a woman by herself (a mistake in bear country, a mistake for men as well) and by keeping calm, she didn’t let him see her was either prey nor as someone to challenge.
A curious bear would have watched at a distance or maybe approached and left. This bear was aggressively pulling up to her for a challenge.
Nope you are wrong by being calm she invited further aggression that is way the bear made contact with her.
She was just very lucky the bear didn’t follow up its attack.