True but it's because people get attached to characters and often stop watching a show if a certain characters die.
Fortunately, other shows like "ER" seem to buck the system.
Even the writers of "LOST" are afraid to kill off Jack.
You are right. I guess that is typical for fans, we do get attached to certain favorites. And who wants to see a favorite being killed off?
And that's not only for TV-shows and movies. I know about an ardent fan of a certain rock band who was very dissapointed when the guitar player left (due to some conflicts) and is constantly trashing the new guitarist and everything the band have done since tie former guitar player left.
As for "Lost", it wouldn't be the same if Jack "left".