This link shows a scatterplot of the relationship across 19 countries between the number of Jews living there and the number of annual new citizenships. The plot indicates that the correlation is weak, but an R-squared of 0.5 is actually very strong.
The obvious explanation is that the Jews, as an immigrating group, will be present in a country to the extent that it is open to immigrants. There is the possibility, however, that the causal arrow might also go in the opposite direction: since Jews would like their country to be open to relatives, co-religionists, and perhaps immigrants in general, a larger number of Jews might exert more influence to liberalize the nation's immigration policy.
Notice how the three countries--Spain, Italy, and Hungary--with a comparatively high number of Jews but little immigration are all Catholic countries--less individualistic countries where it is more difficult for a small group to have much influence on politics.