what if there wasnt any walls in the public bathrooms

I'm just too much of a private person when it comes to "bathroom duties", I would only use such a facility if I was desperate and couldn't possibly hold it. My wife and I (in the privacy of our own home) will pee in front of each other if necessity calls for it but give each other complete privacy when doing the other. I went to summer camp once and the boys cabin had such a bathroom... I was miserable the whole time because I had to hold it until such a time when I could sneak away and go back when activities were going on and nobody was there.

Eventually people will get use to doing it in open public like in the wild.