Banning conversion for the sake of the community

There have been some rather peculiar assertions made regarding the appropriateness - according to both hashgofa and halacha - of a community banning gerim. The comments have not been backed by a single direct source. Let me just bring some sources that seem to justify such an approach.

I have not found any discussion in the literature regarding the ban of the Syrian community. However regarding a similar ban in Argentina, I have found no rabbonim who questioned the right of the community to make such a ban. No one raises the assertions posted in the comments sections.

Besides Rav Kook's approval, there is a discussion by Rav Tzi Pesach Frank in which he approves of the ban and also notes that if any rabbi in the community accepts gerim - against the ban - the gerus is invalid. A similar view is expressed by Rav Ben Tzion Uziel. While the latter did express concern that the tactic might backfire but acknowledged that he wasn't knowledgable about the conditions in Argentina to know whether this was likely.

A clearer proof that such a ban is not inherently problematic is the following gemora.

Yevamos(24b): Our Rabbis taught: Gerim will not be accepted in the Messianic days. This is similar to the fact that gerim were not accepted in the days of Dovid and Shlomo. R’ Eleazar asked which Biblical verse supports this assertion. Yeshaya (54:15) says, He shall be a ger only if he is converted for My sake and only he who lives with you [in your suffering] shall be settled among you.”

Avoda Zara(3b): R’ Yossi said that in the Messianic era the idol worshippers will become converts. But will they be accepted? Has it not been taught that in the Messianic era that converts will not be accepted just as they were not accepted in the days of Dovid and Shlomo? The fact is that they will act on their own as if they converts and put tefilin on their heads and arms, tzitzis on their garments and mezuzos on their doorposts. However when they see the battle of Gog and Magog they will be asked why they have come. They will answer that they have come against G‑d and His Moshiach… Then each one of these “converts” will take off his Jewish signs and leave. G‑d will sit and laugh… R’ Yitzchok said that there is no laughter for G‑d except for that day.

Rabbeinu Bachye (Devarim 21:14): Because of the concern that conversion would likely be done for ulterior motivation, gerim were not accepted during the days of Dovid and Shlomo. During the days of Shlomo they weren’t accepted because of suspicion that conversion was motivated by fear of Dovid’s power. In the days of Shlomo gerim weren’t accepted because of suspicion that conversion was motivated by the power and wealth of the nation. That is because whoever converts from the nations for the sake of material benefit is not considered a valid ger. Even though in fact there were many gerim in the days of Dovid and Shlomo – the High Court (Sanhedrin) was suspicious of them and neither rejected them once they had immersed for conversion but neither did they accept them until their sincerity was ascertained by observing their commitment. Since Shlomo himself converted women and married them and similarly Shimshon converted a woman and married her and it is well known that they did not convert except for ulterior motivation and not according to beis din - the Bible considers these women as still being non‑Jews who were prohibited. Furthermore their subsequent conduct revealed the true nature of their conversion since they still worshipped idols and altars were built for them for this purpose. Thus the Biblical verses write as if Shlomo himself built these altars as it says in Melachim (1’ 11:7): Then Shlomo built an idolatrous altar. That is why our Sages (Yevamos 47b) says that gerim are as difficult for Israel as a skin affliction. That is because most converts have ulterior motivation and they deceive Jews. It is difficult to avoid them after they have converted. Nevertheless we find that gerim are a source of problems and harm for the Jewish people. For example in the Wilderness the eiruv rav were the cause of the making of the Golden Calf. Similarly concerning the demand for meat, the asafsuf (eiru rav) were the source (Bamidbar 11:4). These gerim are the beginning of all bad and the origin of quarrels.

Rambam(Hilchos Issurei Bi’ah 13:15): Therefore the beis din not accept gerim all the days of Dovid and Shlomo. They were not accepted in the days of Dovid because of concern that they would only convert out of fear. They weren’t accepted in the days of Shlomo because of concern that they would only convert because of the glory of the monarchy and the great bounty that the Jews had in those days. That is because whoever converts to Judaism for the sake of physical benefits is not considered a genuine convert. Nevertheless there were in fact many gerim in the days of Dovid and Shlomo because of the incompetent judges. Nevertheless the High Court (Sanhedrin) was concerned that they might in fact be valid converts and therefore did not reject them after they immersed in the mikveh but on the other hand did not bring them close until it became clear what they became.