Here are my results: I am less permissive and more pro-enforcing than the average person who took the quiz. My guess is the people who took the quiz tended to be cold-blooded rationalistic philosophy types, and that skews the average results.
I think an action can be wrong even if it has no harmful effects on anyone, that's because I think there are universal human virtues, like honour and trust, which still hold sway even when harm isn't involved, sometimes even when they can cause harm. Not to an infinite extent or anything, but just as one of many considerations when you judge moral situation.