I don't think this is a BDSM-specific question.

I have known lots of horribly bitchy vanilla women over the years, and they have all been in relationships where they treat their partners like crap. By the same token there are lots of asshole men as well.

I am always baffled, but that is the way it is. Different strokes I guess.....

But back in the BDSM context, if anyone questions your Dominance just because you aren't a bitch, I would question how much they actually know about the lifestyle themselves. Not everyone has the same kinks and attractions, but assuming that all Doms/Dommes/subs/switches fit some kind of cookie cutter mold tends to exist only in the realm of the naive newbie.

Stay true to yourself, and you will find your perfect partner in time.