My one complaint about this article, and a lot of articles of the same ilk, is the part where Americans get criticized for not "traveling abroad" and not "seeing foreign countries".
I suspect most american's will travel more MILES than the average european without ever seeing another country. It's far far more expensive for an American to visit other western countries than it is for the average European. We'd absolutely LOVE to be able to fly to France for the price of train ticket from London to Paris. Sadly, the price of oversees airfare is pretty damned high.
I know visiting different states isn't the same as visiting countries but I think people living outside of the U.S. don't understand just how different various U.S. regions are from each other. Really, you might say it's a bit silly to go visiting foreign countries when you haven't even experienced all of the diversity in your own country yet.