I Stopped Doing My Roommate's Dishes and Mold Grew

I live with two roommates. One of them, Tyler, never does his dishes. For months I'd just wash them because I can't stand a messy kitchen. I stopped two weeks ago to see what would happen. His dishes piled up for TEN DAYS. Mold grew on a bowl. I finally confronted him and he said "why didn't you just say something?" I said I shouldn't have to tell a 27-year-old to wash dishes. He said I "created the expectation" by always doing them, so it's my fault for enabling him. Now he's doing his dishes but is sulky about it, and our third roommate says I should've communicated sooner instead of running a "dish experiment." Tyler says the mold bowl was "passive aggressive." I say it's a natural consequence.