I'm not an American, but I don't really have any issues with it. It's not derogatory to anyone as far as I could tell. Yes, it is glorifying the US army, because it's by an American, for Americans(and thats sorta what they do

), but it isn't a bad song. Its also about supporting your own troops, and being patriotic and they're some fairly universal concepts. If I had good songs about Canadian patriotism I'd probably suggest one be on the PL as well, in order to promote a certain sense of equality among the nations we represent here, but I don't have any songs, so I really can't complain if I'm left out.
That said, a large portion of GSP is American, a large number of players are American as well, I wouldn't wanna pick a fight with any of them over a song, that didn't intend any harm in the first place.
Please understand my point here. I'm not trying to say anyone is right or wrong, I'm just putting my two cents in. It's not a bad or derogatory song, so I say, let them keep it. I'm all for getting along, on the personal, and national levels, and I'd also defend this song if it where for any other country. If they want to be patriotic, let them. Who are we to judge?