Hmmmm...yeah, the problem with men using the women's restroom is that women (hold onto your hats)poo too. Sorry, someone had to say it. I guarentee if a woman had to poo, she would not go in the men's room, and if a man came into the women's room while she was taking care of business, she will throw a giant hissy fit or feel so ashamed that she will camp in the bathroom for hours. That's why women are all "tee-hee-hee" when they go to the men's room, because they don't mind if you hear them pee.
And I agree that the women's restroom is disgusting too. Keep in mind that women aren't just "tinkling" and reaplying lipstick in there. There may not be poo on the floor, but there can be blood in the toilet and urine all over the seats, a failed attempt at trying to squat and aim rather than sit down.