That's how simple it is. If Hamas would have taken such action a long time ago instead of just now there would have been many saved Palestinian lives. Qassams do nothing for the interests of the Palestinians. They never did. It was the boomerang effect and just brought suffering.
U.S. State Dept. condemns 'vicious terrorist attack' that killed Palestinian infant (Haaretz)
from the article: Report: Hamas wants cease-fire with Israel in the Gaza Strip