This topic comes up once every six weeks. Everyone beats the snot out of it. Here is the thing, if told to shut something off or stow something, DO IT!
You are not the boss, you don't know the rules. If you sit there and disagree with the FA or even the pilot, your flight, MY FLIGHT, will be late because they will have you thrown off of the plane!
Put it this way. You are a non smoker and don't want anyone smoking in your car because of the study's of second hand smoke indicate it may cause cancer. You give me a ride and I lite up a cig. You say put it out because of the second hand smoke issue. I say to you "I opened a window so the smoke shouldn't bother you" What part of "it's not your car" don't I understand!
Same thing here. The FAA or the airline said no electronic devices because it may cause interference with the aircrafts electronics. What part of "it's not your airplane or your rules" don't you understand!