It can be argued that those are for warmth, fashion, or utility (such as pockets, or to protect from scratches). But since most restrooms have privacy stalls, you really aren't likely to actually be exposed to another person's genitals anyhow. (If restrooms were made unisex, since you can pee in a toilet, urinals would likely be eliminated).
I imagine transgendered people have been using restrooms without issues for decades, but they were discrete about it and did not draw attention to themselves. For most it would continue to be the same situation if we didn't add all this drama.
Caption this Meme
