Is that really the best reason you can think of to treat schizophrenia? I'd think "so they don't harm themselves or others" might rate a bit higher, just for one example.
I stand firmly for the non-aggression principle. There's no violence against others in self-harm and suicide. And unrequested intervention is aggression.
Keeping crazies drugged so they don't bother their caregivers is pretty far down the slope, in my opinion.