> Kick a group of people out of their homes
> Force an apartheid situation on said group
> Build walls around said group and cram them into small urban areas
> Stem the flow of any form of economy, eductation, and health access
> Act surprised when said group build tunnels underneath wall
> Act surprised when the median age is 16
> Act surprised when extremists take over
Say all you want about Hamas hiding under civilians, but they literally have nowhere else to hide. See the map below, its a tiny-ass strip of land that is almost entirely urban. There is nowhere to go. 95% of them are descendant of refugees. Dropping leaflets and midnight calls warning people to leave their homes in 5 minutes is only added cruelty. There isn't much excuse for using unguided munitions, or dropping rounds on children playing on a beach.
In truth, Hamas was actually supported by Israel in the 1980's, as a counter to their fight with the PLO/Fatah. At the time they only arrested members of the PLO and let Hamas gain a foothold so they would spend more time with inter-fighting than directing anger at Israel. Pretty much analogous to the US supporting the Mujahideen in Afghanistan. Things like that tend to come back and bite.
The US will never end its support of course, with AIPAC buying out congress and our own Christian extremists who think the second coming of Christ will happen only with a state of Israel.