https://mosaicmagazine.com/essay/israel-zionism/2017/11/who-saved-israel-in-1947/
After all, the Jewish people has been closely linked with Palestine for a considerable period in history. Apart from that . . . we must not overlook the position in which the Jewish people found themselves as a result of the recent world war. . . . The solution of the Palestine problem into two separate states will be of profound historical significance, because this decision will meet the legitimate demands of the Jewish people, hundreds of thousands of whom, as you know, are still without a country, without homes, having found temporary shelter only in special camps in some Western European countries.
The Soviet Union voted “yes” for partition, as did its satellites Belorussia, Ukraine, Poland, and Czechoslovakia. (Yugoslavia, another satellite, abstained.)
“They saved the country, I have no doubt of that,” Ben-Gurion would say two decades later. “The Czech arms deal was the greatest help, it saved us and without it I very much doubt if we could have survived the first month.” Golda Meir, in her memoirs, similarly wrote that without the arms from the Eastern bloc, “I do not know whether we actually could have held out until the tide changed, as it did by June 1948.”
for further context they likely did not see the bigger picture because the closest comparision they likely had was the automonous zone they gave jewish people in Russia; there is a state closed off that was given to Jewish people as a safe haven and self governing state (https://en.wikipedia.org/wiki/Jewish_Autonomous_Oblast)
Its still a big L but like other people said they shifted course on this later on, I think they figured it would be like the above rather than what it turned out to be.