It might be insulting to be reminded to wash your hands every time you step into a restroom, but liability's a bitch.
This mentality even though that gaping hole in the plastic seal has probably been sitting there for quite some time. People logic.
If the smell was strong enough, management could go around sniffing people's keyboards and giving mandatory hygiene seminars to the ones whose keyboards smelled like poo.
If I were blind, I could just imagine getting to the end of that sentence and going "eewwwww noooo ewwwwww" and feeling weird about it for the rest of the day.