Brainlessone, you make a very good point but that point could be applied to other demographics as well. Suddenly in America it has become acceptable, even PC, to stereotype all of the Islamic religion. As with the precedent of "preemptive war", that too is an unsettling phenomenon.
You raise the question "which one". But that question could be applied to Christians and Jews too. While the overwhelming majority of Jews and Christians are very decent people, some are not. Re: Christians, how do we know "which ones" are of Christian Identity ideology and extremism and which ones are not? Do we condemn all Christians because some are condemnable? Which Jews are of "frumteen" or similar Jewish supremacy ideology? Do we condemn all Jews? Some Italians, Russians or Jews (and others) are OC/mob members. Some German's were complicate, or had forefathers who were complicate in the atrocities of the holocaust. White Southerners were members of KKK (Koons, Kikes and Katholics). Some males are prone to violence. Some youth are promiscuous, etc. Do we deplore all of humanity became some are deplorable? Humans have an ugly history of atrocities and genocide where religious extremism is typically the cause. Do we condemn or mistrust all groups? The Islamic extremist militants, the ones causing global turmoil and death, trace their hate back to the Crusades, the rise of Zionism and fall of Ottoman. They could probably trace the hatred back to the destruction of the temple. Is this reasonable? We are all infidels, Allah enemies. Are such generalization reasonable?
How do we know "which ones"? Or should Americans give all the benefit of the doubt until it's proven "which ones". Isn't that what our justice system is supposed to be about?