IT WAS front-page news this week when Newsweek retracted a report claiming that a US interrogator in Guantanamo had flushed a copy of the Koran down a toilet. Everywhere it was noted that Newsweek's story had sparked widespread Muslim rioting, in which at least 17 people were killed. But there was no mention of deadly protests triggered in recent years by comparable acts of desecration against other religions. No one recalled, for example, that American Catholics lashed out in violent rampages in 1989, after photographer Andres Serrano's ''Piss Christ" -- a photograph of a crucifix submerged in urine -- was...