Proper responses to aggression?

The Australian media is in a storm today about cell phone footage of a bullied kid responding violently to the bully, and dumping said bully rather emphatically on the ground.  Apparently as a result, both children were suspended, with the bully receiving 21 days, and the bullied, 4.

Some experts are claiming that this response is entirely appropriate, as it is never legitimate to respond to violence and aggression with violence and aggression of your own.  See this piece from ABC news, in which Michael Carr-Greg is quoted as saying:

"It's just moronic to say, hit back. When you hit back and a kid falls over and basically bangs their head and is either dead or brain damaged, is that a really clever solution?"

I am worried about such a response.  I agree that it would be wonderful if bullied kids never resorted to retaliation in kind.  But it would also be wonderful if they never resorted to suicide to escape bullying, and further, it would be wonderful if bullying never happened.  It would be much more likely that kids wouldn't respond in kind if bullying was effectively dealt with by schools, parents, police, or someone.  I would suggest that Carr-Greg's reaction shows a fundamental lack of consideration for the social situation of the bullied child in this instance.  Retaliation is obviously not a clever solution, but that doesn't mean it wasn't reasonable from the perspective of the bullied kid.

Some further features of this particular case that make me think there is an ongoing failure on the part of the school to resolve a tension that reached a head in this incident include the visible size differential and the apparent age differential between the two students concerned.  The bullied kid, the larger of the two in the video, is apparently 16 as compared to the aggressor who is 12 and much smaller.  From this, it should be clear that the larger kid is seen as a bullying target, that others bully him, and that this young kid thought that he too could do so with no personal risk.  I can think of few situations other than one in which the bigger kid was a passive recipient of bullying over a long period of time, that would lead a much younger and much smaller child to deliberately provoke and actually physically assault a larger, older child.

Suspending the bullied child is not the right answer here.  Suspending the aggressor obviously is.  The reason suspending the bullied child is inappropriate is that the bullied child is suffering because of a failure of the school to provide a reasonably safe environment.  This incident wouldn't have occurred if the school fulfilled its duty to protect the kids enrolled there.  This conclusion is entirely consistent with Carr-Greg's claim that retaliation isn't a clever solution, but it acknowledges that from the perspective of the bullied kid, it may well have been an appropriate response.

It should also be noted that this isn't meant to suggest that retaliation would always be an appropriate response, even from the perspective of the bullied.  The particular circumstances of this case are suggestive of a wider issue present in the school.

(As an aside, I cannot help but feel sympathy for the bullied child, and also some guilty pleasure in the obvious aggressor getting a richly deserved and painful reaction to his obnoxious behaviour...  Better that it not happen at all, but also better this than the bullied kid committing self harm or even suicide as a result of being tormented through school.  When blame is to be laid, its the aggressor who deserves it)