I have never heard any christian or anyone else tell us who the synagogue of Satan actually are. When Yosef Mizrachi says its in the Torah, its the Babylonian talmud he is referring to. The John Hopkins institute has DNA study(which is now banned to do in the State of Israel) that said 90% of them, that call themselves jew is Ashkenazi jews, not native to the land of Israel, the other 10% are mostly sephardic jews who came from the Iberian Peninsula.