We can't afford to, no. And we can't afford all the wars that children are fodder in too, in this case as a human smart-bomb.
In answer to the question: the adults who made him carry this out and the western occupation.
Suicide attacks are an unconventional warfare. The only thing that Islam has to do with it is give it a religious veneer - belief in the afterlife and your family being rewarded by god for your sacrifice etc.
I am afraid that that doesn't seem to be correct. Whilst researching recently, I came across this information on Wikipedia:
It is believed that the first bombing attack involving bin Laden was the 29 December 1992 bombing of the Gold Mihor Hotel in Aden in which two people were killed.
It was after this bombing that al-Qaeda was reported to have developed its justification for the killing of innocent people. According to a fatwa issued by Mamdouh Mahmud Salim, the killing of someone standing near the enemy is justified because any innocent bystander will find their proper reward in death, going to Paradise if they were good Muslims and to hell if they were bad or non-believers.
The fatwa was issued to al-Qaeda members but not the general public.This information, if true, would put a clear link between some Islamic scholars and terrorists who would use children used and die in this way. It is no longer a "veneer" but a fact of Islam, even if only a faction of it.