Because they lost? How do you think any nation you're looking at on the map came into being? Those borders didn't just happen, you know. In China, the Chinese who left and went to Hong Kong and Taiwan after the revolution didn't stop to lob rockets back into the mainland and complain. They built a life for themselves. Ditto for the Jewish refugees who landed here and in Israel. Life goes on, for normal people. If you want to keep picking at the scab of past grievances, though, well, you end up dirt poor and stuck in the past and making everyone look at you like you're nuts while you make a big scene about dying with honor.
I certainly see your point tref, but I think these people culturally have a little bit of trouble with forward progression. I don't know enuf about the entirety of the conflict. Lobbing rockets is not the answer, that is for sure.