Many people I know think French are snobs, English are arrogant, Italians are reckless, just to mention few. Although it is possible to understand where these concepts come from (some have roots in their own cultural created notion of inferiority, IMO), and that it is possible to think about a cultural stereotype, I cannot infer all people from the same culture are alike.
This to say I found some sense in this article. I can account a good sleep makes a lot of diference in a positive way. Therefore I don't defend where it comes from, but I agree with most in it.