Because Israel asked us to.

An explanation:

"The recent UNESCO resolutions concerning Jerusalem and Hebron are precisely what terror groups that deny Israel's right to exist, such as Hamas, have long been hoping to hear from the international community.

The first resolution denies that Israel is the sovereign power over Jerusalem, including the Western Wall, while the second one designates Hebron and the Jewish Tomb of the Patriarchs as an "Endangered Palestinian World Heritage Site."

The two UNESCO resolutions, in fact, back the position of Hamas and other Palestinians -- namely that Israel has no right to exist. These decisions provide Hamas and other terror groups with ammunition with which to destroy Israel, killing as many Jews as possible in the process.

Is it any wonder, then, that Hamas leaders were rubbing their hands with glee upon the announcement of the UNESCO resolutions? Hamas can now crow: 'We told you that the Jews are just retrofitting their claims for 3000 or 4000 years of history in this area; now even the international community endorses the idea that Jewish history in the region is a lie...' "