Furiousa is badass as badass gets without sacrificing her core femininity. I dunno why fems would be split on the issue... because she doesn't adhere to traditional female tropes and instead moves closer to a male trope? That character is as close as you are ever going to get to "what's between your legs don't matter" egalitarianism. Which, liberty and expression are supposedly the core values unless I am horrendously mistaken.
But at the same time, Furiosa HAS to be female. The character, as written, would not be a very sympathetic man. And perhaps not an admirable one either.
These are the same sorts that cattily deride stay at home mothers as not being "fully realized" women, aren't they? Anything it takes to feel morally superior to someone else. Except honesty and blunt self-appraisal.