You speak as if terrorists never killed civilians before facebook and isis
Islamic fundamentalists have been killing us infidels and other muslims for decades.
I post this on all terrorist related threads, just for the ignorant.
That's not a good video for your case. The very first thing that Christopher Hitchens does when attempting answer the questioner (after the ad hominems), is to change their question. The audience member asked about this as a reaction to Western interference (colonialism and imperialism, specifically). Hitchens then attacks him for saying "that Western Civilization is the problem". That is an extraordinarily different thing. Hitchens then goes on to attack the notion that Western Civilization is a problem.
One can argue rights and wrongs all day, but arguing that attacks like 9/11 are not at all a response to Western interference is absurd.
Many people like to reject the idea that such attacks are a response because they think it is explicitly placing the blame for the attacks on Western countries. It isn't - the perpetrators of the attacks remain those to blame. However, denying cause and effect, is absurd. And when you take someone's question stating that cause and effect is being side-lined and rephrase it into something else you'd prefer to answer, you're proving the point of that audience member for them.