Jewish songwriters have created some of the most enduringly popular songs of the season — Irving Berlin's "White Christmas," of course, but also "The Christmas Song," "Silver Bells," and "I'll Be Home For Christmas," among others. Some people might view that as a heartening, only-in-America expression of interfaith goodwill and warmth. But not Garrison Keillor: "All those lousy holiday songs by Jewish guys that trash up the malls every year, Rudolph and the chestnuts and the rest of that dreck," he fumed in a recent column for the Baltimore Sun. "Christmas is a Christian holiday — if you're not in...