@SecondJon
Well either that or when you "see it" a moderator talks to the person first to get them to stop doing whatever the amoral act happens to be. As long as you don't insta-ban then strict codified and objective rules arent needed.
With that said not having objective rules can be a turn off to a potential new user since they dont really know if their personal expression is one that is later going to be held against them or if they will be demanded to stop later. Once they are already invested and a few thousand posts in they may not want to find out they are on the wrong instance for them.