I don't think it's a strength problem. The steering loads aren't that high, and I think women can develop leg/neck/core strength sufficient for the braking and lateral loads.
A simulator poses very different problems with comparing drivers (of any sex). The lack of cues is a very real part of "ability" being masked.
If there is a difference, then it's to do with spatial awareness, or coping with adrenaline, or something physiological like that.
Why do women want to compete against men in motorsport, but are happy to have women's football, or women's athletics, or women's press-ups? If women want to be equal in sporting terms, then they should be doing so in all sports, or accept that they need women specific motorsport championships.