It's not the silly hat itself (I've worn lots of silly hats). It's that the hat (and indeed, most of the American flag-themed stuff on offer for the upcoming 4th of July celebrations) is made in China. As if the best way to celebrate that your country is #1 is to do yet another thing to undermine the economy of that country.
Caring about your country is more than just shouting "USA! USA! USA!"