Presenting NB is stressful. People are wired to gender people as one of the binary genders and when there's ambiguity, it throws their circuits off. That's an unfortunate reality about humanity. Some will react nastily to this discomfort, some with interest, others with understanding, but pretty much everyone will find it uncomfortable unless they've put a lot of effort into reconditioning themselves.
A lot of people who adopt non-binary presentations find they need a remarkably thick skin and an understanding that they are going to be noticed, remarked upon, and possibly accosted.
If you are threatened, please be safe. If you do feel safe enough to speak to a stranger, consider doing it from a place of education about what it means to be non-binary.