probably enrages them so much, they just put a bullet in their head , quick and fast
Doubt it. These guys have all the time in the world to do with their captives as they please. Do you really think they'll end a possible propaganda victory over something as simple as spitting at a camera or refusal to cooperate? They would, if they hadn't to begin with, probably torture the hell out of him. Everyone breaks eventually, and when that is the case, knowing that you will die regardless, and cooperating provides a way out of being on the receiving end of more pain...
You have to realize that anti-Western sentiment has existed for generations, and that it doesn't just stop with one generation (or so far it hasn't at least). As for every generation fighting today, there is another being brought up in the terror of what is basically mutual destruction, or an attempt thereof. Hence they have all the time in the world to come up with new ways to make you talk, new ways to inflict damage, new ways to work around obstructions, etc. etc.. Such is the nature of this "conflict".
Religion is a plague that pushes forth hatred through exclusiveness and a superiority complex. Which holds true for Islam, and other religions, when it reaches beyond the domestic household borders and into the public spheres.
I'm looking forward to gunship footage raining down some hellfire, though. Makes for good conversations