Also surprising was Nick Bradbury's report that a law enforcement officer requested that he stop taking videos when he was outside the plane. There is no justification for that unless the person is located in a way that interferes with rescue personnel.
Agreed, such video is highly useful for training and a personal record of your reaction can be of value in a court case.
More to the point it seems likely that there was something better for the policeman to do than harass passengers.
It is not unusual in a serious emergency for police to go into "law enforcement" mode when they should be in "serve and protect" mode. Police airwings are not immune either.