Damn, those Volokh folks are more “loose” than I thought. Sex! Nudity! Pissing! Groping! Smoking (they presumably mean tobacco, I would be thinking more along the lines of ganja)! All fair game for serious consideration.
If one were to coax a view of “public” property rights out of me on these, I would analyze it as a combination of recognition of a property-right vacuum due to the status quo & a personal space issue. In other words, 1) though it should not be the State’s property, it wouldn’t be yours anyway unless it was your town, so it’d be rude to assume you can piss on it if the locals aren’t doing so & 2) if you can’t bring yourself to ask if they want to see you nekked then it’s not a good idea to assume the answer is “yes”. Although, speaking as a man, I’d say if you are a woman that looks like Salma Hayek you should be allowed to go outside naked whenever you damn well please ;^)
An obvious note: they’re the law guys, I’m just me. Discussion would be welcome about this here, but be warned I may not know what you’re talking about if you start rattling off court case citations.