It was fair and relevent to report on this incident. The incident occurred at a function where the Mayor was attending in his capacity as both an elected offical and most relevently as the cheif exectutive of his county. The idea that working hours were over when this occurred is not relevant. 

If the Mayor were at a private function of a friend, where his presence was purely personal and not as Mayor, then it would be questionable if such an outburst would warrant reporting. But that was not the case here. Any elected offical attending a meeting related to their public capacity , whether that meeting is on the officail's island or somewhere else in the world, needs to represent themselves with decorum fitting their being a representative of their constituency. Have a drink or two, if you can maintain proper decorum, but if you cannot, understand the consequences are this behavior will impact your public perception.