Even then, Jews arrived in southern and then parts of western and central Europe well before they were making their way to Russia, and they faced rabid antisemitism there as well. It’s a plague that moved eastward and northwards to Russia with the spread of (European interpretations of) Christianity, not something originating in Russia nor spread west by it. European Jews were moving into Poland, then Russia fleeing persecution, they weren’t fleeing the other way around.
Even then, Jews arrived in southern and then parts of western and central Europe well before they were making their way to Russia, and they faced rabid antisemitism there as well. It’s a plague that moved eastward and northwards to Russia with the spread of (European interpretations of) Christianity, not something originating in Russia nor spread west by it. European Jews were moving into Poland, then Russia fleeing persecution, they weren’t fleeing the other way around.