Reuters: A Gulf of Mexico deepwater drilling ban has already cost offshore jobs in a nascent U.S. economic recovery and a lengthy moratorium will put the industry at peril, sector executives said on Wednesday. Their remarks came a day ahead of a court hearing on the moratorium imposed by the Obama administration, which says it is needed to prevent a repeat of the BP Plc well blowout that brought environmental havoc to the Gulf, polluting beaches, killing wildlife and scaring away …