The debate is endless, and you can find ample evidence to support any point of view. Israeli supporters can cite a myriad of examples, wherein groups like Hezbollah and Hamas provoked Israel, leaving no choice but retaliation and justifying civilian casualties. I would put this type of argument in the "effect" camp- a simple acknowledgement of the present circumstance. What I am more interested in revolves around "cause". What conditions existed to allow Hamas and Hezbollah to rise to such prominence? Is Israeli policy culpable in allowing extremism to fester?
I would argue that these groups thrive, and the ones prior as well, as a direct result of oppressive Israeli policy. I begin with a sympathetic view towards the Palestinian cause, and what person who cherishes the ideals of basic human rights wouldn't. The world community failed the Palestinians miserably, while the new tenants seemed to forget the lessons of discrimination. Acutely aware of repression, it is especially frustrating to watch Israeli's act without sensitivity. No reasonable person could conclude that the Palestinian people have been treated with dignity and respect, more like an inconvenient afterthought. The result of this approach creates an environment where hopelessness thrives, and people search for anything that appears to confront the perceived "occupiers". You can argue until the cows come home, but from the Palestinian perspective that is the justifiable reality that is the state of Israel. The world wanted a Jewish homeland, forgetting that this land wasn't exactly empty to begin with. Is it any wonder that the forgotten people are "radicalized"? I don't buy the argument that Palestinian culture is pre-disposed to violence, anymore than I did the ANC during their struggles. When you have no options, no one champions your plight, you live in object poverty with little opportunity, then extremist views find fertile ground. This condition finds references throughout history and isn't culturally specific.
Does this justify terrorism? No, but it brings some perspective as to how we get to this present state. Peel the onion, find the core and deal with that reality. Arguing on the margins only serves to temporarily remove a problem, which inevitably rises again. Unilaterally deciding where, when and how withdrawal will take place is not a solution, because it doesn't treat the other party as an equal. This entire vicious cycle is a question of dignity, until that is addressed in a respectful way, expect things to remain the same.