The reason for the fighting has nothing to do with whether it is war.
And the war started before Israel even existed, you can't blame Israel's actions for it. The fundamental cause is the existence of a non-Muslim government on land they considered conquered their own.
People who lived there considered it their land. 'Conquest' is irrelevant.
Every piece of land in the world is governed by someone who took it from someone who considered it theirs.
And every piece of land in the world has been taken at some time by conquest; usually several times.
If the fundamental cause of strife in the Middle East was as you say it is, the whole planet would be a war-zone.
The US Government exists on land that the British considered conquered. But the British dominion of Canada does not fire rockets at the USA; British/Canadian fanatics do not blow themselves up on buses full of of-duty US soldiers; and the USA doesn't allow fanatics to settle in enclaves on the Canadian side of the 49th parallel, protected by a wall that encroaches North of the border in loads of places.
Clearly your 'fundamental cause' is not sufficient to explain the situation.
There is nobody in the Middle East who is blameless, and Israel is at least as blameworthy as anyone else.