On the contrary, by your definition, the United States was founded by "extremists". They gave up everything and went to war for their ideals. How much more a "purist" or "extremist" can you get?
The success of the American Revolution and the American System is that the extremists and the Purists did not take over as it happened in the French revolution for example. There were no "Robespierres" among the the Founding fathers who thought that they are more pure than the others and began chopping the heads of their opponents using the guillotine. Thank God that the Founding Fathers were not Purists or else we would not have had the United States of America as we know it which is the greatest nation in history of mankind.
You want to be a Purist pelase feel free to be like this but in America you as a Purist is a bitter loser and you will always remain as such. You cannot win, ever.