Rabbi Gold's main point is the circumstances have changed since Rabbi J.B. Soleveitchik (Rabbi Lichtenstein's father-in-law and teacher, often-quoted in Rabbi Lichtenstein's letter) ruled land could be ceded for reasons of pekuakh nefesh (to save lives). But what Rabbi Gold fails to make clear is Rabbi Kahane Shapira is opposed to ceding land even for reasons of pekuakh nefesh. Further, Rabbi Kahane Shapira's ruling contains internal contradictions as noted by Rabbi Lichtenstein. Rabbi Gold disengenuously does not address these issues, and therefore his 'answer' is no answer at all.
It should be noted that Rabbi Kahane Shapira has himself refused to answer these questions as well, perhaps because in truth there is no answer that is acceptible halakhicly (in Jewish Law). Rabbi Kahane Shapira and his followers have illegally elevated shleimut ha'aretz (unity of the land) to the position of a cardinal mitzva (Divine commandment), a mitzva that overrules all others including pekuakh nefesh. This is akin to idolotry. Worse yet, it is strikingly like the theology of the zealots of the Second Temple whose zealotry lead to the Temple's destruction and almost 2000 years of exile.
Rabbi kahane Shapira owes all of us a clear response to Rabbi Lichtenstein's letter, one that addresses all points and answers all questions. Until he does so, Rabbi Kahane Shapira should not be viewed as anything other than a zealot whose zealotry has led him astray.