So first of all, congressmen were not elected under the Articles of Confederation. They were chosen by the legislatures, one per state regardless of population. It would be hard to be substantially less democratic. (The Senate was similar until the 17th amendment, as you no doubt know).
Second, the whiskey rebellion was AFTER the ratification. I was talking about people's response before ratification. I assumed you were too when you said "nobody would stand for it" if it happened today. Right enough, if you take umbrage at how a new government is being set up, it is generally best to object _before_ it is in place and has a militia.
As for the "extraordinary claim," I have already given the reasons it is extraordinary, which is why I did not repeat them. The ratification conventions that were held for the Constitution were, for all their flaws, one of the most broadly democratic things that had happened on the face of the earth to that time, certainly in such a large country. (Switzerland, of course, like some ancient Greek city-states, was a direct democracy; these were, however, far smaller).
For sources, I'll have to refer you to Akhil Amar's "America's Constitution: A Biography." I left my copy at home, sadly, so I can't quote it to you. He discusses these issues in quite a lot of detail.