Rav Hirsch writes in his introduction (page 1-2):
“In the spring of 1962, a group of the most preeminent halachic authorities in the United States gathered to discuss the plausibility of an eruv in Manhattan. The meeting was chaired by HaGaon R’ Aharon Kotler zt”l, in the presence of HaGaon R’ Moshe Feinstein, HaGaon R’ Yaakov Kamenetsky, and HaGaon R’ Eliyahu Henkin zt”l among others. While there was (probably) no unanimity of opinion concerning the issue from an academic standpoint, an absolute consensus was reached toward an halachic prescription. They publicly declared that “it is impossible under any circumstances to erect an eruv in Manhattan and that it is forbidden to carry even after all the improvisations that have or will be implemented by any rabbi(s).”
If Rav Eliyahu Henkin zt”l was at the meeting as Rav Hirsch claims why then didn’t he sign this kol korei (see The 1979 Flatbush Kol Korei Exposed). Therefore, his statement that, “an absolute consensus was reached toward an halachic prescription,” is untrue since Rav Henkin abstained from partaking in this prescription against the establishment of the Manhattan eruv. In fact in 1960 Rav Henkin signed on to the committee to establish an eruv in Manhattan (Divrei Menachem, O.C. vol. 2, p. 10; see also Kisvei Hagriah Henkin, p. 33 where he urges the rabbanim of the Bronx and Brooklyn to erect eruvin). Additionally, most rabbanim at that time were in favor of the eruv in Manhattan such as: Rav Tzvi Eisenstadt, Amshinover Rebbe, Kapishnitzer Rebbe, Boyaner Rebbe, Noverminsker Rebbe, Radziner Rebbe, Rav Michol Dov Weissmandel, Rav Yonasan Steif, Rav Tzvi Pesach Frank, Rav Menachem Kasher, and the Shatzer Rebbe, zt”l. In Iyyar of 1962 an eruv was established under the supervision of the Shatzer Rebbe. Only after the Manhattan eruv was established did this aforementioned meeting of the, “preeminent halachic authorities [Agudas HaRabbonim],” take place and then they issued a kol korei against the Manhattan eruv.
It’s important to note, when Rav Moshe zt"l signed on the 1962 takanah with Rav Aharon Kotler zt"l, we see that he was not at ease with the language, since after he quoted this takanah in his teshuvah, he omitted the last line which stated that, “those who rely on the eruv in Manhattan are considered a mechalel Shabbos” (Igros Moshe, Addendum to O.C. 4:89).
“R’ Moshe, who was a member of that convocation, maintained that although that prohibition was issued only with regard to Manhattan, its relevance extended to the whole city of New York, minus the clearly defined exceptions, i.e. Queens (Kew Gardens Hill) etc.”
This is pure fiction since Rav Moshe zt"l never stated that the 1962 issur against establishing an eruv in Manhattan included all of New York City. This is a fabrication of the 1979 Flatbush kol korei (see The Community Eruv kuntres, Appendix 10). If Rav Hirsch is correct then when the rabbanim of Flatbush asked Rav Moshe for his p’sak about erecting an eruv (Igros Moshe, O.C. 4:87) Rav Moshe should have referred back to the 1962 kol korei and stated that the issur then included erecting an eruv in Brooklyn. Not only did Rav Moshe not declare that it was prohibited to construct an eruv, he was not mocheh and did not even recommend that they not erect an eruv (ibid.). What he did tell them was, “I do not want to join you in this matter, because there are many opinions on this topic, as we see in the Shulchan Aruch.” Only when some people misunderstood these words as somehow supporting the eruv did Rav Moshe feel there was a need to clarify his personal approach regarding the issue. Hence he wrote this teshuvah clarifying his opinion, explaining that he had a chiddush, which accordingly would prohibit the construction of an eruv. However, he declined to issue a p’sak, since, as he acknowledged, his chiddush was not mentioned in the Achronim, and moreover it was obvious that the Aruch HaShulchan would not agree with him.
Rav Menashe Klein shlita wrote (Oim Ani Chomah, siman 7) that Rav Moshe told him in 1979 ― in the presence of Rav Elimelech Bluth shlita, Rav Shalom Dresner shlita, and Rav Mordechai Tendler shlita ― that contrary to what someone in the Agudas HaRabbonim was promoting the 1962 issur from the Agudas HaRabbonim was only regarding Manhattan. More so, Rav Tuvia Goldstein zt”l, a Talmid/Chaver of Rav Moshe zt”l, said on numerous occasions that even after the 1979 kol korei against the Flatbush eruv was published, he spoke with Rav Moshe who agreed that if the rabbanim wanted to erect an eruv they could do as they saw fit. Moreover, he stated that even Rav Moshe himself would have allowed an eruv in its present construction. Therefore, we can’t extrapolate what these signatories of the 1962 kol korei would maintain regarding Brooklyn and definitely not their stance concerning the present eruv.
“The attempt to construct an eruv in Brooklyn flies in the face of rabbinic consensus.”
Again there was no consensus and where is it stated that there is a need for a rabbinic consensus when constructing an eruv? On the contrary, every rav has a responsibility to establish an eruv in his town (Teshuvos V’Hanhagos, 1:844; see also Chasam Sofer, O.C. 99).
“New York City already has its ruling. It must not be ignored!”
Even if there was a ruling, the Bach (Choshen Mishpat, siman 25) states that after the passing of a rav other rabbanim, even in his hometown, can make permissible that which he had forbidden. More so, since regarding Brooklyn Rav Moshe was misled (regarding the population size and mechitzos) the Mharsham (7:48) brings the Rivash and the Mharashdam that to begin with there is no din of chacham sh’osser.