OK, let's assume there was a mass hallucination at Mt. Sinai. Why, then, would the Bible indicate that G-d said that no other nation would EVER receive a national revelation like Israel did at Mt. Sinai? What is the point of saying this? If you were Moses, or Moses and a bunch of close confidants trying to start up a new (and lucrative) religion, WHY would you put something like that in the text? Because, you see, if only ONE thing in the entire text is wrong, then it isn't the Word of G-d, it is just a bunch of crap, end of religion. That claim is not only unnecessary to the text, but it (claims made in the future) is something that cannot be controlled by any humans.
Oh, BTW, in the last 3,300 years, not one nation has made a claim of national revelation. That's not "never," but its a pretty good record, wouldn't you say?
Get a grip, and at least attempt to read the entire post. I wrote all of those words with the assumption that people here would read all of them and not just knee-jerk react...as you have.