even if you include every Islamic extremist or sympathiser anywhere in the Middle East, the overall number of people glorying in the effect of the strikes in NYC/DC is pretty small in world terms.

Cap'n, I have no doubt that you are factually correct.

But I find only limited comfort in the fact you note. Unfortunately, we've seen what can be done by those who, though only a small minority world-wide, are in one particular locality numerous and organized -- especially if they are there strong enough to influence the government of that particular nation. (Indeed, I suspect we could fairly say as a generality that the most extreme atrocities, e.g. Hitlerite Nazi Germany, are perpetrated by a small minority.)