I believe the reason is very simple. The right wing has never proposed a realistic alternative. Basically, they want to keep the status quo. As the old saying goes you can't beat something with nothing. Many people have come to the realization that the status quo cannot continue. It is simply untenable for a whole host of reasons. Therefore, people will grasp at any straw that is offered to them. The latest one is disengagement. The average Israeli wants to live his life in peace and not have to worry about suicide bombers etc. The left at least offers such a possibility, the right does not.
I strongly oppose disengagment both on religious grounds (see R' Shachter's article in the RJJ Journal about land for Peace) and political/security grounds. Appeasement never works and disengagement just projects weakness to the Palestinians which they will be quick to exploit. There is no doubt that the majority of Palestinians believe that Tel Aviv is a settlement and that they want to return to Yaffo. Disengagement will fuel the fire of groups like Hamas.
Given all of that, I have to say that the right has not presented a tenable alternative, as I said status quo is untenable.
I believe that transfer is the only real option, however, it is not a realistic one in 2005.
Even the left wing Haaretz commentator, Danny Rubinstein, echoes the security arguments. He writes Second Thoughts
...The argument for second thoughts stems from the events of recent days, which raise fears that a unilateral withdrawal from Gaza is causing serious security damage to Israel.
The fact that a majority of the Palestinian public sees Israel's decision to withdraw as a sign of the victory of the intifada has long been known. It is hard to argue with this. Years of a peace process and negotiations between the Palestinians and Israeli governments, including Likud governments, have not led to Israeli withdrawal from Gaza. The idea of withdrawal entered the mind of Prime Minister Ariel Sharon only after suicide attacks, Qassam rockets and mortars.
Even if these attacks were not the reason why Sharon came up with the idea of disengagement, the Palestinians are certain that that is the case, and this has reinforced their belief that Israel only understands the language of terror attacks and violence. This belief will now become an absolute certainty - if Israel withdraws unilaterally under fire.