Half the population is under 18. Of those over 18, no one under their mid-30s was eligible to vote in the last election in 2006. Of those who could vote in the last election, less than half who did vote actively supported Hamas. Collective guilt is irrational in Gaza now, and was irrational in Germany and Japan then.
By your own arguments, all Israelis are guilty of every act by the government of Israel against the Palestinians. You are justifying Palestinian terrorist retaliation in your own logic.