Gene Weingarten's controversial humor column, Below the Beltway, appears every Sunday in the Washington Post Magazine, generating more mail than Santa gets at Christmas. Not all of it is wildly condemnatory. Some of it is only mildly annoyed. He is also reputed to be close to persons thought to be familiar with individuals claiming to be authoritative spokesmen for the mysterious and reclusive Czar of The Style Invitational.