On the contrary. A Shewee or PStyle allow you to we in such a way that anyone coming around sees nothing. Except the wee itself. If you are wearing trousers you do not need to expose anything more than a man does. Less, even, because all that sticks out of your clothing is the device.
If you're wearing anything else, yes, you have to uncover yourself. But you can still keep yourself away from the filth, as there is no need to squat.
Also very useful for women who cannot squat, for whatever reason.
(And no, not all women can aim.)