A bear is a known a danger and really doesn’t care about you unless you piss it off. In fact, loud noises might just scare it away even if a brown bear.
While most men are probably safe enough to have around, enough are unsafe or just generally give off that vibe that women don’t want to be alone with them and a loud noise won’t scare them away. You might “know” you’re safe but they have zero reason to trust you.
Sure she might get someone who wants to work together to be mutually safe and will make efforts to leave her be otherwise, but she might also get someone who stands just a bit too close, who starts trying to “help” just a bit physically, or even who starts to get frustrated when they don’t get some kind of reward for just being some minimum level of decent. And if they’re really unlucky they get someone who just sees the isolation of the situation as an opportunity.
The bear is a known quantity. The man could be anything and there are far too many examples of every part of the spectrum. At least the bear won’t sexually assault her even at the worst.