I don't think we're being warned. I think people are letting their imaginations get the best of them. If the point of prophecy is to prevent it from happening, then a successful prediction is a false one, and I think you and I can both see the logical fallacies you run into once you accept that.

If Nostradamus is the real deal, by what mechanism does this prophecy work? Can he actually see the events of the future? How? By what channel is information breaking all known laws of physics and actually traveling back in time to the brain of a bad French poet? And why is the channel so bad at getting the details through?

Remember that he also predicted the apocalypse would occur at the end of the last millennium, but it didn't happen. If I recall correctly he even named a specific month that all sorts of world-ending shit would happen. However, I'm sure all the Nostradamus gurus have imagined some new interpretation of that verse that explains away the problem. They always do when their predictions don't happen.