No, their argument isn’t that “we are likely to poison ourselves,” it’s that New Orleanians were being poisoned. This assertion seems incontrovertable.
As to “the professor,” I don’t agree. As I explained before (and do at more length in THE POLITICALLY INCORRECT GUIDE TO THE CONSTITUTION), earning a J.D. doesn’t require obtaining any knowledge of constitutional history. Unfortunately, being hired as a law professor after obtaining a J.D. seems to confer the impression that one is expert in constitutional history. This is a very unfortunate combination.