You've presented some interesting historical information, but I don't think it justifies your pro-Israel conclusion.
1. You acknowledge that modern Palestinians have more genetic commonality with the ancient peoples of the Levant than Ashkenazi Jews have. Then you go on to say: "If genetics creates claims, then they [the Ashkenazi] have a pretty good one." What you don't say:... If genetics creates claims, modern Palestinians have an even better claim.
2. You mention in your body text that the mystical and devotional Sufi movement was independent from rulers, and was good at winning converts to Islam. However, in your conclusion you forget all about the Sufis. You declare that Muslim rulers "drove out" most people who were there when they arrived, and that the number of converts was "modest".
3. You emphasise the "mind-bogglingly egregious" conduct of the Palestinians in the period 1919 to 1948. You don't consider whether this was a response to the mind-boggling arrogance of the British Empire as demonstrated in the 1917 Balfour Declaration, when the Empire failed to consult Palestinian Arabs at all before announcing the plan to create a Jewish homeland in Palestine. And the mind-boggling arrogance of the League of Nations in endorsing what Britain was doing.
4. In your final paragraph, you say: "But if tomorrow Israel abolished the civil rights of its Arab citizens, my views might change!".
Don't you know there are millions of Palestinian Arabs in the occupied West Bank and Gaza who have never been citizens of Israel? These millions of Palestinians have few civil rights to abolish.
Don't you know of the Palestinian diaspora who are denied the right of return to their homeland? According to Israel, any claim these Palestinian exiles may have had has been extinguished by less than a century of absence.
Yet diaspora Jews, whose families have been absent from the region for almost 2 millennia, do get "right of return" under Israeli law.