And we're talking three (or more) generations in many instances who have been stateless refugees in Gaza. 70% of the population are classified as refugees. It's hard to convince people that they simply need to keep their heads down and work toward something when they have living proof all around them of it coming to nothing, and there are few people in Gaza that haven't experienced profound loss...of their homes, of people they know, with zero recourse because they basically exist in a land with no real legal system, given that it's not a state, but also not governed by the laws of Israel. If your home is destroyed, or a loved one is shot by snipers, well...tough break, better luck next time.
Hopelessness, anger and idleness -- given that Gaza basically hasn't had an economy since the blockade was initiated 15 years ago, the unemployment rate is astronomical -- is a breeding ground for extremism, and no amount of bombing is going to fix that.