Japan had no such trouble selling their war for they were religiously committed to die for their God Emperor.  

While jihadists are well motivated to fight their jihad and to protect their culture to the death, many Americans (and much of the west in general) have different priorities--American culture as it currently exists is simply not worth preserving.  This is why the great educator Bill Ayers can stand on an American flag, why the great preacher Jeremiah Wright can "damn America," and why the great mentor Frank Marshall Davis can lobby for the communist model in front of a gullible future American president.

Sure, they by and large enjoy(ed) the standard of living here, but they do not like that some have less than others.  They like that some people have good health care, but they are unwilling to accept that others will be without.  

Leftists like the idea that they have complete freedom when it comes to living their own lives, but they resent that others might discomfort them with cigarette smoke, might fight environmentalist demands that ever more expensive houses be built to satisfy ever more stringent building codes, and might resist ridiculous taxation levels on the most productive members of society to enable a spreading of the wealth not only here but worldwide.  

America is simply not their model of society. Why fight to preserve a country that is so imperfect?