Some people were hinting that there was some kind of anti-Americanism in there, but I didn't need to worry: it's as pure as NIPPON STRONK as promised, and rolls very easily so far. It certainly has a potential to fall apart, but it haven't happened yet. The characters are quite nice and I'm quite enjoying my time with them, even Pen'ya and Risa. This really is the key ingredient that makes this anime tick.
I noticed that a few bloggers tended to take GATE more seriously than they perhaps should have. Doing that is just wrong, and even has a potential make one self-identify as a blind ideologue.
As to anti-Americanism, that peaks in episodes 9 and 10 of the first series.
Pfft. There wasn't any, essentially. Not to the extent of Read Or Die.