Listen up, folks: Don't beat yourselves up, there's plenty of crazy Saudis willing to do it for you. I don't have a problem with attempts to identify the ''root causes'' of 9/11, only with the particular root cause everyone settles on--to wit, poverty. The late Osama bin Laden was a wealthy man. Loaded. Mohammed Atta and most of the other killers belonged to the privileged middle class. Omar Sheikh, who kidnapped and beheaded the Wall Street Journal reporter Daniel Pearl, is a British ''public'' (i.e., private) schoolboy and graduate of the London School of Economics. Saddam Hussein's personal fortune is estimated at $7 billion, a career in public service in Baghdad being rather more lucrative than one in, say, Copenhagen. And let's not forget the representative two or three hundred Saudi princes currently accompanying King Fahd on his convalescence in Spain. A lucky London escort agency has landed the contract for servicing the Saudi swingers: The gals all have to be blond and they're replaced every two weeks, having been thoroughly, er, exhausted by then.