Did you heard about Pale of Settlement in Russian Empire? Jews was not allowed to live outside Pale of Settlement. Uman, Dnepropetrovsk and Odessa was towns where most Jews live at the time. In Uman is some rabbi grave. It is a place of piligrimage of some Jewish sect. Jewish Ukrainian government provide security and assistance for them. This will not be the case if or when Uman will be liberated by Russia. Most probably, Jews will flee from scary awful Russain orcs to the elven West or whatever.