Israel has already said there were rocket-launcher sites adjacent to the building, but that the building was not a target and hitting it was a mistake. Does the video show rocket launchers actually on or in the building?
Reports are that the missle struck adjacent to the building (where the rocket launchers were) and that the concussion of the blast pancaked the building holding the cowering women, children and old men.
Launching rockets next to a civilian shelter is a clear war crime by Hiz, precisely because this kind of disaster is often what results. In fact, I imagine Hiz WANTED a big pile of bodies for their propaganda war, because the usual suspects will blame Israel for the response and not Hiz for the clear war crime of dragging civilians into the conflict.
It was not too many years ago that the expected way to take out such an installation would be several bombers carrying 30 or so 500# bombs to be sure that the whole area was saturated with flame. Those who are violating the "rules of civilized warfare" here are not Israeli. For anybody unhappy about this specific tragedy to be blame Israel for it in any way shows how far out of touch with reality they are.