I don’t get into fights about the boro park eruv. That’s because rav pam said not to; he was very sad to hear that almost half of boro park carries, “uber machlokes is erger,” were his words.
But he didn’t defend the flatbush or definitely not the Brooklyn -wide idea, as far as i know. I don’t think it was even a hava amina in his time
On that, i don’t mind getting into arguments