...Possibly because most of them are facing the passengers, with their backs to the screens whilst pointing out the exits.
However if something erroneous occurs be it an incorrect safety video or something more serious such as ice on the wings, it is better to question it than wonder 3 months later if it was "illegal" or not.
As far as the safety briefing is concerned, virtually all of it is common to all types save for the exit positions and operation. There is a default in that the operation is also shown on the safety card that the passenger is directed to read, and the location that should be manually pointed out.
Obviously it is not right if the wrong video is shown and it should have been detected before presentation, however in an imperfect world an error detected or suspected by a passenger can be questioned at the time.