>>510969255 (OP)Because their religion tells them to. Any other answer is cope.
Jews have always lived in Israel. They became a minority in the region gradually over 1600 years of arab colonialism, ethnic replacement and religious persecution. Under the Ottoman Empire, the arab colonists of the empire were afforded privileged status to maintain their loyalty and state control over valuable holy sites. When the Ottoman Empire collapsed at the end of WW1, the arabs of the Empire lost their privilege.
Tensions between the arab and jewish population of the Levant began immediately. The arabs rioted, lynched jews and confiscated jewish property in an attempt to solidify their colonial mastery over the region now that their state benefactor had disappeared. I say "arab" because "Palestinian" didn't exist as a national, cultural or ethnic identity until the birth of Israel. They self-identified as muslim arabs, spoke arabic and followed arab customs.
The british intervened in this violence, having been assigned the mandate of Palestine by the League of Nations. When the Mandate came to an end after WW2, the arabs of the region banded together and launched a war of extermination against the jews. They lost this war, and lost it badly. The state of Israel was formed by jews successfully defending themselves from an attempt by their colonists to exterminate them.
Muslims have collectively seethed about that defeat for half a century now, in part because their holy book demands that they kill non-muslims wherever they live, and in part because the truth of their millennium-long project of racial supremacy and religious imperialism being destroyed on the battlefield in an embarrassingly one-sided war is humiliating. Above all they just want to erase the truth about their history and recast themselves as the indigenous of the region, but the fact that their victims are still alive completely undermines that narrative.