To repeat, my point isn't "Islam has no part to play in Islamic terrorism" nor is it that we should pay no mind to specific religious or national tendencies of oppositional groups. My point is that the fundamental root of anti-Western and anti-American attitudes might be more readily located in nearly 100 years of brutal, unilateral intervention than in the character of Islam. My second point is that to posit Islam as the fundamental cause of this retaliation is practically to ignore the fact that this is retaliation in the first place. It might be retaliation marked by specific cultural tendencies, but it is retaliation. To focus on the specific character of Islamic retaliation seems to be a dishonest means of downplaying (or, at an extreme, tacitly accepting as legitimate) the multitude of ways we've contributed to the rise and spread of violent Islamic extremism, and it effectively obscures discussion of how we might act to stop the spread of extremism (beyond, of course, "keep occupying, keep bombing, keep supporting status quo dictatorships, etc."). To generally answer the question of why Islamic retaliation seems unique, again, I haven't really got an easy explanation for this (it's not something I've done much research into), but I think I've already provided a few things to consider. 1) We weren't actively supporting, financing, arming, etc., say, some form of violent Latin extremism at the same time we were conducting brutal terror campaigns in Nicaragua, Cuba, Guatemala, etc. 2) Like I've said (and to massively generalize), areas in the Middle East have a culture of retribution that's fairly distinct from the rest of the world, and we've actively fanned the flames of this tendency through continued support for Islamic extremism and through a handful of wars of aggression, assassination campaigns, etc. As for more specifics:

but this also homogenizes islamic terrorism. the uprisings in iraq, for example, are understandable results of military occupation. how do you explain people that aren't being occupied, aren't being bombed, etc by the west joining islamic terrorist organizations that are transnational? the only nexus for these groups and people is islam, or rather their interpretation of islam. why does someone in jordan care that the US is occupying afghanitan or iraq? they see it as an attack on islam. why do they care that there are military bases in saudi arabia at the behest of the saudi monarchy? they view it was an attack on islam. not every uprising or suicide bombing is as easily traceable to US interventionism as the iraqi insurgency. CLEARLY there is something that links these people together beyond the nationstate, and that ideology is islam.

One might suspect the population of Vietnam isn't currently incensed because we aren't currently occupying Vietnam -- this is a pretty simple explanation. As for why we didn't see much domestic retaliation during the war, the answer is also fairly straightforward: the US didn't have a large Vietnamese population during the war. The vast majority of Vietnamese Americans immigrated after the 1980s.

but international terrorism didn't start after 9/11. muslims were hijacking planes and killing westerners outside of the middle east decades prior. what prevented the vietnamese from doing the same at the time? why weren't there munichs and lockerbie bombers in the 70s? i mean it's not like the vietcong weren't extremists either.

Again, I haven't done much research on this (though lots of good research is being done on the question of "homegrown terrorists"), so I can only speculate that this might arise out of general feelings of persecution, desire for community, desire to participate in something "bigger," etc. As it stands, however, I don't think "because Islam" is enough of an explanation on its own.

but this would apply, probably even more so, to american blacks and native americans in the 21st century. there is a common thread of radicalization either through the internet or through radical preachers, that pushes these young people into becoming the way they are. but again it's not like there aren't radicals in the black and native american communities. there is SOMETHING about the islamic ideology that helps this. long story short (unless you want the long story, in which case i'll get to it tomorrow) islam, mostly of the middle east variety, did not go through the enlightenment phase that much of the rest of the world did (largely thanks to the ottomans) and islam itself, being a highly decentralized religion, didn't go through the reform periods that catholicism did. you can see this too in protestantism. much of the most radical christian preachers and ideologies spawn from the protestant faiths because they lack any kind of top-down hierarchy that prevents abuse of the 2000 years old social mores that make up the religious texts.