Actually, it is all about the Founding Fathers- specifically, these founding fathers.
Imagine if you had a job where you can run around the country blabbing about whatever and have people throw money at you and feed your ego.
You do know candidates can not legally keep donated money or spend it on themselves, right? It is not like Barr or whatever candidate (including McCain and Obama) is going to take a Hawaiian vacation with their respective remaining donated money after the election.