Najaf IS holy, to Siite Muslims. It is Al-Sadr, NOT us, who is desecrating the Mosque.
Unlike Westerners, Arabs do NOT consider mere buildings to be "holy;" in fact, there's a large article in the Wall Street Journal of a couple days ago about the difficulties experienced by those trying to preserve the Arab "heritage" by preserving historic buildings.
Muslims consider it idolatry to attach any particular siginficance to a mere building, so this "respect" for Muslim "shrines" is purely a creation of we ignorant Westerners.