Interpretation is always involved, but that doesn't make it arbitrary. Everything we do as moderators follows from the principles of the site—intellectual curiosity and civil, substantive discussion.
> don't write down
It's impossible to write everything down, it would be boring to try, and the reward for such foolishness would be even worse behavior. The commenters who most poison internet forums are experts in adapting to rules so they're technically not violating them.
> I'm arbitrarily enforcing our culture's unwritten sanction
Sure, there are many such values and there are tradeoffs between them. In this case the need to protect the commons takes precedence, because it's fragile and worth protecting. There were other ways to make the substantive point behind your comment.
