Al Qaeda's problem is that unlike Hezbollah or Hamas, they have no infrastructure wing. No one from Al Qaeda is going out there and delivering food or repairing buildings in the aftermath of the destruction they're involved in. They don't fund orphanages or health care clinics. All they do is kill people. For all their talk about how they're going to destroy America, they mostly kill Muslims. Al-Qaeda and Osama bin Laden can try to associate themselves with the struggle of the Palestinians, but few see them as fighting for the same reasons, which is possibly why so few Palestinians join Al Qaeda. Al Qaeda's support for the Palestinian cause is a public relations scheme to excuse the kind of indiscriminate killing some Muslims are finding increasingly unacceptable.
Or, as the former leader of Al Jihad and Islamist theorist Sayyid Imam al-Sharif, AKA Dr. Fadl put it, “the Palestinian cause has, for some time, been a grape leaf used by the bankrupt leaders to cover their own faults.”
-- A. Serwer