The statement in bold makes no sense. Doing something until you get caught is neither some crazy "unwritten rule" nor is it saying "it's cool to do this as long as you don't get caught". It's a rule, you break it and get caught, you get punished. That's why they exist. To quasi-quote Walter from the Big Lebowski: "This is not 'nam Thomas, this is football, there are rules." There is very little grey area required here, outside of those that seem to want to look for it (the NFL included).
The comparison to baseball is completely irrelevant. Especially with the amount of nonsense that goes on in baseball under this "unwritten rule" guise.
To me, this is nothing about being a moral policeman, it's the fact that the Pats have been caught TWICE now doing things that are against the rules. The impact at this point is, and should be, unimportant. It's the fact that they will willfully break the rules that should be the problem, and the overarching concern for the NFL.
What makes it even WORSE in my opinion is that I fully believe that the Pats are a good enough team to win without cheating. Yet whomever truly is the mastermind(s) of all of this are so insecure or whatver it is, that they still go about breaking the rules for every advantage they can conceivably get.