Comment by dralley

Also, if you were a European Jew in the late 1940s after the fall of the Nazis, you were still faced with the prospect of living under the local governance of Nazi collaborators, continued pogroms [0] and antisemitism, and potentially Joseph Stalin's USSR. It's not like everything immediately went back to normal, either in real terms or psychological ones.

[0] https://en.wikipedia.org/wiki/Kielce_pogrom

It's unsurprising that many wouldn't want to reintegrate with that society after what they experienced, even if they managed to avoid the camps (and especially if they didn't).