Well, If I've caused you harm by crapping in the common area, then require me to repay the damages. In this case, the cleaning bill. At that point, you may also decide that crapping in the common area was a breach of our original contract when we got together to purchase the building, and if you can prove it, then you can kick me out. This is likely, since I doubt many joint ownership agreements would not include a "don't damage the common areas" clause.
So as long as you crap in the driveway, or similar place where no cleaning is required because it will eventually rain, everything is fine. No harm/damage done?
We don't want to kick you out, you contribute in many ways to our apartment complex, we just want you to start using regular toilets. A majority of us residents can not put a rule in place where we fine anyone who craps in our common areas, not because it directly damages anyone, but because we want that behavior to stop?