It's frustrating to argue with you, because you did not bother at all.
First of all: it's not Hamas, even by what Israel said. It's Islamic Jihad.
Secondly: it wasn't on purpose by that argumentation, it was a failed rocket launch. It would not be the first time a militant group with makeshift rockets had an accident, although this would be particularly lethal.
It's astonishing how much passion you put into your comments while refusing to actually read about what you talk about.