Personally I think sewage would be extremely !!fun!! and an excellent addition to DF, allowing both for better farming and for the inevitable weaponisation. If Toady is squeamish for some weird reason (he does it too, why would it disgust him?), then he should just make it possible for modders to add it.
Because right now DF is "that really complex game that makes great stories" and he's worried that, with this addition, it'll become "that really complex game with piss and shit all over the place".
You mean that's worse than mermaid farming, dwarven child care and shield babies ? Everything that needs to be found by moral guardians/ill-intentioned people to attack Dwarf Fortress is already in the game.
DF is simply ignored by these people because it is not mainstream. Also people do not pay for it.
I agree that it will probably bring some bad publicity, though, and there are more important things to do.
It WOULD be nice to use manure (both animal and dwarf) as a replacement for potash, though. Call it filth since it is already in the game ?
Edit: Now I am thinking of nest boxes and the LAYS_UNUSUAL_EGGS token... :O