The Palestinian people have suffered a lot. Their suffering started even before they had a crystallized identity; like many other nations that were formed as a reaction to a colonial movement, even the boundaries of the Palestinian nation was defined by its adversary - the Zionists. In every conflict, on every turn, the Palestinians lost more and more. Most Palestinians have been thrown out of their home and had to start a new life in a foreign environment at least once. The entire Palestinian experience is one of deportation and oppression, usually by Israel, but all too often by fellow Arabs.
The Jews have had a history of 2,000 years of persecution, of fleeing from one place to the next, of never having a place to call their own, and never having any status by right, always being a guest in some other country, always existing at someone else's goodwill. Jewish existence in Europe was dotted by all-too-frequent pogroms, so much so that the English word "Pogrom" originates in the Yiddish. The communities in the Moslem world suffered systematic discrimination, often accompanied by daily ritual humiliation.
The tragedy of the Israeli-Palestinian conflict is that both peoples are not really interested in bringing it to an end. Both sides are far more interested in recounting, re-narrating, re-telling their sad, sad story, both to themselves and to others. This sole precious possession of a story in which "we" are so innocent, and "they" are so unquestionably evil, is seen as an ultimate asset: we have right on our side. The fact that this position perpetuates the mutually insufferable wars of the past decades somehow is lost in all this rightness of the story.
Most people on both sides have some vague concept of why the other side deserves sympathy, but they are far too busy pitying themselves to really notice what is happening on the other side, or to look to the future. Amazingly from a human point of view, they are genuinely more interested in being right then in anything else, such as enjoying nature, culture, life. Like two children locked in a quarrel, both are more interested in "who started it" (maybe the Romans? maybe the Turks?) than in having a fruitful discussion of the future. Both sides worship the sacrifices of their martyrs, and scorn the people who emigrate for a better life elsewhere. Wanting a good life for yourself is somehow seen as selfish, even treasonous.
Personally, I am an Israeli from a Jewish family originating in Hungary & Lithuania. My family suffered their share during WW II, and also during the wars of the Middle East.
There are two possible lessons to be drawn from the genocide of WW II, and both can be summarized by the words "never again". One lesson is: "we will never allow such a thing to happen again, neither to us nor to anyone else". This is a Moral conclusion: some things (racism, genocide, violation of Human and civil rights) are simply not done. The other lesson which can be drawn from WW II is: "we will never allow this to happen again to us". This is a particular lesson for "us", the Jews: The world is full of evil things, and let's not be victims any more. This conclusion leads very readily to the accumulation of might, and ultimately to the meting of such abuse on others that we, were we subject to this same abuse, would raise all hell, and with good cause.
Sadly, this second conclusion seems to be the one that Israel is drawing. During the wars of ex-Yugoslavia, when Bosnian-Moslems were subjected to concentration camps and starvation, Israel saw no special reason to intervene, since it was not us who are the victims – not our business.
It is a well documented fact that most child-molesters and other sexual criminals have been the victims of similar crimes themselves. The victim recognizes all too clearly that in the criminal situation there is one person who has power (the criminal) and another who has not and therefore suffers (them). A common conclusion that is drawn by victims (especially those that do not get counseling) is that the world is a bad place with all sorts of cruel people running around, and there is no-one there to protect the innocent; so in order to not be the victims they need to choose the other option, sad as it may be: be the perpetrator.
Similarly, The Jews justify their abuse of the Palestinians in terms of their own historical suffering; and the Palestinians justify their own crimes (International terrorism is to a large degree a Palestinian invention) by reference to the evil things that have been done to them, mainly by Israel.
So far, so depressing. However, it gets worse: The picture of sulking self righteousness is also a feature of wider inter-cultural relations. The (Judeo-Christian) west feels betrayed by the third world that does not appreciate all the technology and progress provided by western culture. Similarly, the Moslem/Arab world feels hard-done-by for being in its current unappreciated predicament. Both cultures have a self image of being very advanced, civilized, and gentle. However, both are seen from the outside as being insatiably greedy and imperialistic.