I can't condone this as a disciple of Jesus Christ. Vengeance is mine, says the Lord, and that's because He's the one who has the right to exact it.
But I try to be nothing if not honest: I know I shouldn't find this satisfying, but a very real part of me absolutely does. Who saw the videos of the beheadings, or of burning people alive, and didn't quietly imagine doing the exact same thing to these beasts if given the opportunity? Not that you would, but you thought about it. And then again, maybe you absolutely would. These Iraqi soldiers got their chance, and they didn't pass it up.
Disturbing? I guess people have to say that. I'm not sure that's really how most people feel about this happening to the people it happened to: