The main point of the whole thing is not that Americans would be idiots, but rather that the way the United States is being governed is very suboptimal to the wellbeing of the average citizen and average inhabitant of this planet (yes, the way Americans live, how much they consume, has a great impact on every single human being on this planet).
Many points made are very clear, and well supported (e.g. income equality: http://www.ted.com/talks/richard_wilkinson.html).
As it happens, I have similar political views with author of the infographic, and I admire Northern European countries. But that doesn't mean that I have something to criticise about the USA. My home country is way behind in terms of government transparency, and liberal, free-thought of its population.
"Very sub-optimal"???
You think it doesn't matter "to the wellbeing of the average citizen and average inhabitant of this planet" that we e.g. keep the sea lanes open and the price of oil lower than many producers would like it? Or prevent another hot world war?
Good snarking! And on a serious note, I think the main comment here isn't about the actual issues, it's about Americans reaction to them. We appear to be OK with this or at least not willing to do enough about it.
[Edit to counter a bit of my snark: I'm not saying these aren't problems, I'm just complaining about the stupidity of listing all of these more-or-less known issues and then grouping all Americans into a lump and asking us why we're all such idiots. The United States is a gigantic, complex nation of hundreds of millions of people whose voices need to be filtered into some kind of governmental consensus. It's not at all fair to compare the US to a Scandinavian country.]