"He replied with, "So what if I show up on your doorstep and just start moving my stuff in?". "
Like what happened in 1948?
To over a million Jews in Arabic countries who were forced to leave.
Exactly, just like my local police will back up my "right" to keep my house and property on what used to be land that belonged to the local Paiute tribe.
What would have happened to Arabs in Israel in 1948 if all the surrounding Arab countries had not declared war on Israel and attacked her?
Nothing. All the Arabs living in Israel would have kept their property and gone on living as they had done previously, albeit in a new state, rather than under the Turkish Ottomans or British mandate.
History lesson: Jews had been in Israel even after the Diaspora imposed by the Romans 2000 years back. The Arabs wanted nothing to do with that region, as they thought that desert was too harsh even for them. Jerusalem, oddly enough, was a predominately Christian city for the centuries following the Crusades.....it had a minor Arab population at best.
The reason the muslimes want Israel eliminated is found in the Koran, the Sunnah and the Hadiths: Any land occupied by muslimes, even if stolen from someone else (in short, when muslimes become squatters), is muslime forever (hence, the reasons Arabs still call Spain "al-Andalus"....it dates to the time before the Reconquista, and they have never accepted the Spanish reconquest of the Spanish homeland from the muslimes). Thus, the small Arab population (negligible, actually) present in the Holy Land when the Zionist movement began to resettle Jews in Israel in large numbers viewed the Jewish return as a violation of islime, and the Jews needed to be destroyed. This led, by the 1940s, to an Arab alliance with the Nazis (the Mufti of Jerusalem, Arafart's uncle, was a welcome guest several times in Berlin, and the Nazis raised some muslime Waffen-SS divisions, most notably "Handschar" in Bosnia), and the adoption of a "final solution" and "judenrein" attitude among the Arab countries toward the nation of Israel.
Bluntly, the Arabs are the interlopers. The Holy Land has been Jewish for 4000 years, and as a Catholic Christian, I will support to the end my Jewish bretheren in their fight to keep their promised homeland. God gave the Jews that land....and no idol worshipping followers of a pedophile false prophet can overrule God.