I don't defend the boy's remark, but he is a boy and it was meant as a joke. We can't rely on everyone to behave sensibly all the time, least of all sixteen year old boys.
The JMC spokesman recognised it was a joke but seemed to think it had endangered people's lives. It's a pity people no longer seem able to deal with such a matter without throwing the book at the offender.
Bring back Dixon of Dock Green.