US policy toward DPs was hugely different in 1945 and after than
If the Israelis had a hold out position on/near the coast, Haifa and/or Tel Aviv, say, then the RN and other navies would no doubt rescue a few thousand from there. But where are they going to go? Look how very few Jews the US took before WWII. I'm sure a handful of thousands of refugees could be rescued and resettled. Although they may be in refugee camps for years before a permanent home is found.
No. I suspect that close to a majority of Jews in Israel would be dead in this scenario, and the remaining ones worse off than OTL's Palestinians.
I imagine a token rescue effort would be made, but it would be too little, to late.
US policy toward DPs was hugely different in 1945 and after than it was in 1940 and before, obviously. The Displaced Persons Act of 1948 and (amended) 1950 led to the emigration of some 415,000 European refugees; this was less than half of the 900,000 emigrants from Europe in the immediate postwar years.
The total population of Israel in 1949 (Jewish, Christian, Moslem, etc.) was under 1.2 million, which was less than the population of Nebraska in 1950 (total US pop was ~151 million).
Given the willingness of President Truman to recognize Israel and (generally) turn a blind eye to arms purchases from US-controlled stocks (including, at one point, the planned acquisition of an escort carrier), I would expect that if the Israeli population was truly endangered, the 6th Fleet and then UNRRA would be in a position to rescue any that so chose to be rescued...
Even today, with an Israeli population of ~8 million (of varioius faiths) the entire population of Israel numbers less than that of New Jersey or Virginia....spread across a nation of 312 million (2010 census), it would not be much.
Actually, there's a POD for what could be a pretty interesting AH - at any point in Israel's history, have the majority of the population call it a day and emigrate to the US...
Best,