Gun stores... typical "alpha male" place unfortunately. Being yourself as an employee will elicit a response and that's unfortunate.
Here in NJ we are a bit more progressive (but we are AWFUL for gun rights) but some gun stores still have the typical alpha hotels behind and in front of the counter. I don't think I've ever encountered worse customer service than at some gun stores. Especially if you're not a good ole boy straight out of duck dynasty. The good news is that there are nicer more upscale gun stores and ranges that cater to a diverse clientele. For example a friend of mine runs a range and he says everyone walks in, from hasidic Jews to lesbians openly PDAing each other. He welcomes all of them, he doesn't care as long as they spend money and enjoy shooting. The last place I bought a handgun from, the person who sold it to me was an intelligent woman who served in the marine corps and who is also an instructor.
Women are increasingly taking up shooting and even LGBT are doing so. Did you know the plaintiff, Tom Palmer, in the CCW case in Washington DC is gay? He bought a gun to defend himself as he was previously attacked because he is gay. So there is hope. Hold your head up, as you said, people are buying... but you will need a thick skin to deal with the idiots.
You might also want to look into joining pink pistols. They are bascally an LGBT gun rights organization.