As one who has been insisting that Israel takes its share of the responsibility, I can't let you away with the notion that Hamas can totally escape any. They're still firing off Qassams at Israel, which is destructive, inhuman and pointless. Yes, you are right that the Qassams are not the reason for the attack on the citizens of Gaza. But the Qassams give a continuing pretext. And the people of Gaza suffer.
Palestinian youths throw stones at security forces in Shoafat, E. Jerusalem; none injured (Haaretz)
from the article: Too many authorities