If all you have is today's moderator's personal feelings about what kind of comments are passive-aggressive and what sort deserve a ban, how is that any better

If all you have is today's moderator's personal feelings about what kind of comments are passive-aggressive and what sort deserve a ban, how is that any better than codifying it as a standard? You don't need a massive rule book, but surely having some basic rules is better than having none? If you don't have rules, then what, it's just personal judgement on how I feel today about what you said today that rubs me the wrong way and I hand out a ban? Come on, it's daft. Communities need to feel like there is a strong consistent moderator presence in them; if you're all over the place doing whatever, the community will fall apart into arguments and spam; there are countless examples of it. The difference is when the community is small (ie. many software projects) its probably perfectly easy for one single moderator (eg. the project owner) to be consistent and thoughtful in how they handle the community. ...but that model doesn't scale.