Several here basically think the same as Al Qaida does. Al Qaida sees what the US government has done in the past and does now as evil, and says that therefor any US citizen, or anyone cooperating with the US is a valid target.
Some here are saying that the US should nuke Mecca or the ME if NY is nuked. Currently there are a few hundred thousand extremistic Muslims at most in Afghanistan and the Pakistani mountains, and maybe several tens of thousands more worldwide. They also bomb Muslims who they see as 'too Westernly', and yet people call for nuking the holiest city in Islam. Which basically would in an instant create a few hundred million more 'terrorists', and people will want revenge for the killing of millions of innocents. Or do you really think that the extremists are in Mecca?
Not to mention that the fallout clouds from nuking the whole ME would not only annihilate Israel, India and SE Europe, it would also destroy a large part of Russia. So the moment Russia sees loads of missiles going that way, a similar number of missiles flies to every major US city.
I wonder if the results would not be far more deadly if they got their hands on Ebola than on a nuke. Smuggling people over the Mexican border isn't that hard, and if they go with a reasonably large group, infect themselves and then fly all over the US thousands or more will be infected before it is even noticed, and many millions will be before real action can be taken. Closing off the exits to one major city may be possible, but what if they have people in all major cities? If one hangs out at Wall Street, one follows a White House tour, etc, the economy and government take an extremely serious hit.
Edit: Added a few missing words.