One of the reasons Americans have such a hard time putting this into context is that history has been so drastically gutted in the name of math and science education in our schools that we have produced a woefully ignorent cluster of generations. In this same vein, it also makes it very hard to compare the US on a wartime footing to Israel. Even during World War II, supposedly our most "total" war footing ever, the home front wasn't making sacrifices on the scale seen in the UK and elsewhere. There was much *talk* of sacrifice, but the action was really small by comparison. Even the Civil War touched the Northern populace in very small ways, all things considered (since if you had enough money you could pay someone to serve in your stead during the period of conscription). And it left most of the West (California, Utah, the territories) untouched for the most part (aside from the brief Texas campaigns in 1862 or so).

Most of America's wars have been short, and very few of them in the last 100 years or so have really threatened our existence. We don't really have an experience of war to draw on, and we're so used to our wars being distant, packaged, and almost sanitized for public consumption. This, I think, makes it easier for the protester community to take the stand it does. It also allows the far Right to take many of their positions.