In this past weeks hebrew Mishpacha (a Chareidi weekly), there was an article about this issue. It quoted the Tolna Rebbe saying that he doesn't understand why the Chareidi population isn't doing anything. The chareidi piopulation is ready to protest the possible desecration of old graves in the construction but not the disengagment.
I believe that a large part of the answer is the following. The Chareidi population and leadership in many ways feel vindicated. For 50+ years they have been warning the dati leumi not to participate in society, etc. how the chilonim will never accept them etc. Now their predictions are coming true. The chiloni world has turned on the Dati Leumi in many ways. The army, is now talking of closing down Hesder Yeshivos or at least disbanding their units. Even before that there have been major problems with the role of women in the army. Of course, the disengagement which is affecting mostly Dati Leumi. Therefore, in a way, maybe even unconsciously, the Chareidi world wants the disengagement. They want the Dati leumi to see the light. The Chareidi world believes that the Dati Leumi will now become more Chareidi in light of these events. Because the Chareidi world has never believed in the state giving back land is not a big deal to them.