Ok, so cost and cleanability might be incentive so have doors like that, but not incentives to make regulations.
Those regulations likely there for "decency and safety". E.g. to discourage people having sex, or to make it more obvious if someone passes out. That is: the regulations really are there to make reduce privacy.
There might be good arguments for reducing privacy, but that is still the proximate goal of the rules.
Haha, probably cocaine as well. Some public restrooms seem designed to minimize flat surfaces, private access to clean water, and secluded locations, while others (like in some night clubs) have randomly placed shelves with hard, easily wipeable surfaces, etc.
Those regulations likely there for "decency and safety". E.g. to discourage people having sex, or to make it more obvious if someone passes out. That is: the regulations really are there to make reduce privacy.
There might be good arguments for reducing privacy, but that is still the proximate goal of the rules.