As has been suggested previously, that's flawed thinking, as it implies that "bashing kids" (which wasn't exactly what was filmed in any case, was it?) add to the "ranks of militants." Of course, it doesn't add to these ranks, as the militants (or at least the type of person that thinks it's reasonable to throw missiles, shoot people, deliver bombs and slit people's throats) already existed, and if the piece of film did anything negative, it was merely to give these people something tangible that they can spout about to people that are, of course, gagging to hear it in the first place.
But of course, even this is of no consequence if our media had the guts to simply report the footage, show it, comment that there is absolutely no indication to suggest that the commentary has been provided by anyone other than a newspaper hack, and that it's a simple illustration of rough justice being handed-out to people that entirely and unreservedly deserved it.