Most Helpful Guy
I'd say that it isn't because you're "scary" but because you aren't the type of girl that guys who would just approach girls would go for. The kind of guy who casually hits on random girls is looking for someone bright, open, fun and easy looking. A goth girl doesn't really look like a good time to them so they won't bother. But then again you probably wouldn't want a guy like that either.
Just be yourself and you'll eventually find kindred spirits