The rabbis of the Talmud were seemingly ambiguous on the question of the return of the descendants of the deported ten tribes to the land of Israel. Through mass conversions Median Jewry in ancient times became so large that settling in the largely agricultural land of Israel may have seemed unfeasible at the time. That the Israelites had married with the converted Medes was also implicitly acknowledged. There was also understanding that the religious practices of Median Jewry was significantly different from that of rabbinic Jewry. There is of course also the rabbinic opinion that Median Jewry will only return at the time of Mashiach, in messianic times.
Among the rabbis are only the most senior Haredi poskim (rabbinical decisors) traditionally aware of the identity of core Median Jewry. For the Israeli government rabbinical recognition of the Jewish personal status of Median Jewry is a critical component in the process of Median Aliyah. The cooperation of senior poskim in the process of Aliyah is therefore absolutely essential. The case of the Sabbateans (so-called “Dönmeh”) in Turkey is instructive. The rabbis have traditionally excommunicated the Sabbateans due to their nominal affiliation with Islam despite their initiation into the Bektashi order, one of nine denominations of core Median Judaism. This is a complex issue because on the one hand could the rabbis not accept nominal apostates and on the other hand could they not reveal core Median Jewry for fear of exposing them to persecution.
Anti-Zionist Haredi rabbis are generally opposed to the Jewish return to the land of Israel prior to the coming of the Mashiach. Other Haredi rabbis are more ambiguous on the question of Aliyah and are generally not opposed to Aliyah prior to messianic times. Senior Haredi poskim would obviously not volunteer to reveal the identity of core Median Jewry to the general public but it would be different if the Israeli government did it first backed up by comprehensive science from the Mossad research division in documenting Judaic practices of all denominations of Median Judaism, including core Median Judaism and reconstructing the trajectory of their shared world history.