We don't really need toilets in this game.
Because it doesn't bring anything new or interesting gamewise.
Now, there's certainly good reason to have trepidation about the subject, and I can respect an argument where someone just honestly says "I don't want toilets because I think it's gross and/or immature," but statements like "this doesn't bring anything new or interesting," is being either intellectually dishonest or willfully blind.
People just said what it would do that is new and what it would add: Verisimilitude, sewer systems and the possible logistic challenges that come with them, fertilizers, and a source of lant/ammonia, whose value as a chemical has made it invaluable since nearly the dawn of civilization. (Used for fertilizers, dying, cleaning agent, chemistry, and one of the primary components of virtually all explosives known to man, including gunpowder.)
If you can't think of any ways that any of those things change the game, you're just trying not to think about it at all.
(And while we're at it, let's take vomiting out of the game - that "doesn't add anything", right? (It's not like a consequence for subterranean isolationism is a "new" thing, right?) Or is the standard simply that once something is in, it becomes dogma, but if it has yet to go in, and it's not what you want, it's "not adding anything new"?)
It's fine to be opposed to something, but at least be honest about your reasons.
What makes this topic so frustrating is that any time someone tries to have a mature conversation about what it means and what it can do, there will always be a vociferously vocal minority of people who declare that there is absolutely NO way to have a mature conversation about the topic... and then simply treating all reasoning to the contrary as nonexistant.
You don't get points for prophecies you make self-fulfilling by going out of your way to sabotage anything that goes against your predictions.