I agree this isn't an NCL problem. Just about all cruise lines have gone through this at one time or another. As mentioned, the cruise lines are held to a higher standard to report if more than 1% come down with Norovirus. Whereas on land, hotels don't.
I agree it would be very upsetting to fly so far to be notified. However; you were given a choice and you chose to take the cruise. This is another example why everyone should buy insurance.
I sailed on a Disney cruise a week after they had an outbreak. They were not letting anyone get their own coffee or drinks either. This seems like an appropriate way to try to avoid further spreading.