@ExXB
Statement from Southwest Airlines as quoted in the article:
Our hearts go out to the Evers family during this difficult time. Flight attendants are trained to notify the captain if there is an emergency that poses a hazard to the aircraft or to the passengers on board. In this situation, the pilots were not notified.
Maybe cabin crews are so used to having to make passengers stop using their phones (on practically every flight) that the situation has become generic -- they no longer consider if there's a real reason or justification for any phone's continued use. I think this just human nature... not really a "fault" per se.