I understand that a line has to be drawn somewhere, and frankly it doesn't matter how far back either's claim goes - there are significant numbers of Palestinians and Israelis who have only known the current boundaries and any changes fundamentally alter their identities. Sure, we can go into the genocides committed against the Jews in the region over the past 2000 years that expelled them from the area and gives cause to antisemites that call Jews "white", or violence perpetrated by Europeans when breaking up the Ottoman Empire and stoking ethnic violence over the past 100. But those claims only matter to the extremists as wedge issues used to divide.
Extremists shouldn't get to determine the future of millions who clearly want to live peacefully together. No one can bring back the murdered, but Israel, regional powers, the US, and European countries owe it to humanity to rebuild the destroyed cities in the same fashion that we intend to rebuild Ukraine.
If that is simple to you, then you really haven't done any research into the subject. Would you call the native tribes of Oklahoma colonizers after they regained much of their land from the state? Of course not, because it's not as simple as I've described it - imagine a non-native Oklahoman calling the Chickasaw colonizers because suddenly they are in the jurisdiction of that Nation? That's what extremists sound like, using charged words that evoke emotions from other situations unlike the one described.