The study you linked doesn't absolutely say what you are trying to make it say (that there aren't fundamental differences in psychology between men and women). It seems to say that male and female brains and cognitive abilities aren't as dimorphic as their genitalia, but instead there is a continuum and overlaps for many distinct cognitive traits. In other words: (almost) all men have normally formed penises, (almost) all women have normally formed vaginas. Mixed situations are rare. Brains are another matter, genders mix and overlap. That doesn't mean that there are NO genders though.