Baldwin may in fact be a jerk... but take note of the fact that there were a lot of people a few seats away who had their own phones turned on and who were tweeting about the incident as it happened. The flight attendants weren't getting on those people. He was definitely singled out.
Furthermore, this was one of those situations where they put the plane out away from the gate and then sit in place for half an hour or more, with the seatbelt sign on and all, for no good reason. I was once on a flight where the plane sat still on the taxiway for nearly two hours, and they absolutely refused to turn off the seatbelt sign.