You say that like it's a bad thing.
Personally, I can't think of any more fitting way to deal with islamic terrorist scum.
I actually have very mixed feelings about it. Killing someone is not as easy as people think. Once you've crossed that line .. very difficult for life to return to normal.
I can understand the anger .. and it would certainly be justified. However .. I'm totally against vigilante justice .. I think it denies the rule of law - which is what America was built on.
To stomp on the guy and bust him in the chops would be fine with me; just let him survive. Send him to GITMO and let him spead the word that the American people will fight them in the street if needed.