100% Disagree
It’s an underdog story about classism in which the folk hero (Johnny) is confronted by a powerful man (the Devil) who tries to exploit the hero’s perceived ignorance and inferiority by offering a great reward with impossible odds. Although Johnny warns him that looks can be deceiving, and that he’s going to regret the dare because Johnny is the “best there’s ever been”, the devil is blinded by his greed and arrogance.
The devil creates an awful cacophony of technically excellent fiddle playing that would be impossible for Johnny to replicate. It’s a trick.
But Johnny just grins at him and starts to play “simple” classic country fiddling songs - Fire On The Mountain, House Of The Rising Sun, and Daddy Cut Her Bill Off. He doesn’t rise to beat the Devil - he simply creates his own music from his home, in the style that he knows, and his love of it and the familiarity of the music make his “backwoods” fiddling more perfect than the Devil could ever achieve.
It is thus the devil’s pride, not Johnny’s, that allows Johnny to Bugs Bunny his way into a golden fiddle.
(In that sense, I do agree that it is the most American song: in a land of prejudice and inequities, great power lies - dormant but ever-present - in those we underestimate and attempt to exploit.)