The Network views television as a life consuming poison. Something that should be turned off and stay off because of its deceitful nature. The audience seemed to be infatuated with the man standing in front of them yelling. The main message was that television was not reality, it consists of lies.
The irony is three-fold. One, the man is attempting to get people to listen to him about turning off their televisions while he is one television. Two, he is preaching that nothing on television is real and he collapses to his death while he is on television (how can you get more real than that). Three, the audience applauded his death because they thought it was an act.
His message was not entirely wrong, however. The average American turns on the television and turns off the brain. We sit day in and day out as drones on a couch not really doing anything but wasting time. Only occasionally does something worth while get absorbed.