It’s obvious...they’d evolved so far that they never excreted, much less have it stink.
As James Doohan replied when asked about that very question, “Why did we need bathrooms? We had phasers.”
There were bathrooms in everyone’s quarters, they just never showed them.
Really, how often do you see someone on a non-SF series visiting the john?
There were bathrooms in everyone’s quarters, they just never showed them. They don’t show them in any of the six Star Wars movies, either...or in the Alien films...you get the idea. BTW, there was a great book that came out during the late Eighties (about the time of Star Trek IV) called “Mr. Scott’s Guide to the Enterprise” that I still have, with enough info about the refit Enterprise to send any nerd to geek Nirvana. It even had floor plans for crew quarters, and there was a “refresher” in each one. Even some of the department maps (like recreation, IIRC) had refreshers on them.
And anyway, how often do you see someone on a non-SF series visiting the john? Other than Al Bundy, it’s not an issue. I’ve never seen Michael Weston’s bathroom, for example, or his Mom’s.
One thing that was funny was that when a role playing game company (I think it was West End Games) published a map of the interior of the Millenium Falcon, there wasn’t a bathroom anywhere on the ship. Since your average hyperspace trip takes a few days (and in the WEG rules any trip took at least 24 hours) it appears Han and Chewie were carrying a large chamber pot around...or maybe there was a portajohn in the cargo hold.