Of course the same could be said of Lebanon, which the Israeli foreign ministry celebrated the other day:

Five years ago yesterday, on 24 May 2000, Israel completed a unilateral withdrawal from southern Lebanon. The UN Security Council certified that the withdrawal was in full compliance with UN Security Council Resolution 425. Today, Israel’s primary objective regarding Lebanon remains the same as five years ago - ensuring the security of Israel and its citizens and promoting stability and peace in the region. Israel believes that these goals can be achieved through the full implementation of all relevant UN Security Council resolutions.

The problem is that since Israel's withdrawal from Lebanon none of those "relevant" UN resolutions have been followed, (except nearly five years later the Syrian withdrawal from Lebanon). The Lebanese government has not fulfilled its obligation to take control of its southern territory and Hezbollah still attacks Israeli positions (military and civilian) accross the border.
Worse, Hezbollah, no longer defending itself on its own territory, has expanded its operations as is regularly reported these days and was documented back in 2003. (Israel's proving that "the best defense is a good offense" by its absence.)
There are those who focus on how Israel's withdrawal from Lebanon was a victory of Hezbollah. While that's certainly important, it's not the main reason to be skeptical that disengagement from Gaza will carry a high price for Israel in loss of its security. If a "victory for the terrorists" was the major concern, Guy Bechor's argument, "Leaving mistakes behind" would carry a lot of weight:

Palestinians arriving in Gush Katif after the pullout should find vacant land, just as it was left. Moreover, instead of building Palestinian youth and leisure centers, perhaps, for the first time in their history, they would direct their attention to rehabilitating their refugees.

If that were the end of it, one of the most serious objections to disengagement would be answered. Alas that's not the case. Now that Hamas will no longer have to worry about defending its home base in a few months its planning to expand its operations even more. The Jerusalem Post reports, "Report: Hamas moving most of operations to W.Bank":

Hamas was relocating its headquarters with the consideration that once Gaza is under Palestinian authority, their battlefront would move to Judea and Samaria, Army Radio quoted sources in the security establishment.

In other words, Israel won't be silencing a dangerous flashpoint by withdrawing, it will be opening a new front. Not only will Hamas be able to shoot its Kassams without harrassment, Hamas will be able to expand its operations against other parts of Israel from its new base of operations.
Israel's presence in Gaza wasn't just about the biblical views of a few people. For one thing, many of Gaza's residents aren't religious (such as Aryeh and Datya Yitzchaki) and they appeal to Israel's historical connection to Gaza. Many also previously gave up their homes for peace by leaving the Sinai. But the most important reason for staying in Gaza is to contain Hamas. Haberman obviously wouldn't want to admit or consider any of this. It's more important for him to mock the anti-disengagement folks he overhears than to give serious thoughts to what might be the flaws of the plan he so enthusiastically endorses.
Crossposted on Israpundit and Soccer Dad.