When I was on holiday in Florida, we just stood out (accents, fully clothed instead of wearing little clothing like most the people I saw over in Florida), some Floridians called us snobs for being British I ignored it.
Americans are not proven to be stupid, neither is any country. People can be proven stupid, you can't say one country is stupid because of 5 or 10 people, that's just ignorant if you do. That video could have been made up with Canadian, Mexican, British or French people then the title may not be something like "Americans are NOT stupid...". You could say that about any country but you can't prove it is stupid without doing research on billions of people in the world.
Notice that Americans basically control the world on many things, they may not have invented most things but they certainly are not stupid. So saying Americans are stupid is complete bollocks.