In my opinion, just because we belong to the same group - i.e., humans, we're not the same.
Women and men often view the same things very differently, have different objectives and place different values on things. Women may also prioritise things differently to men and whilst men have one way of doing things, women sometimes do them differently or not at all or vice versa.
In addition, women are often much more emotional than men, yet can also be more pragmatic. We are essentially both sides of the same coin.
It's not surprising therefore, that men have difficulty understanding them, but I am talking generalities here.