It might not be targeted at Jews, or perhaps not just Jews.
Maybe they see it as a blanket vulnerability - millions of people who could blend in perfectly in Russia, that have been subject to recruitment and training by foreign intelligence services. Perhaps they have caught a few spying on them.
Another possibility is that some number may have been muslims, who now reside in countries that used to be part of the Soviet Union. They may not want a large population with easy access to Russia, who might be getting radicalized in mosques beyond their control.
Or maybe they don’t want the people who have seen the Western world to be able to return. TV propaganda would not work half as well on them and they might tell other Russians uncomfortable things a about the world.