I will start by saying that I loved this movie. I am surprised to see so many reviews about this movie being about reality TV or look at it like it is supposed to be realistic. To me using this plot with the reality show is simply to be able to tell a much more meaningful story about life and death and the power of empathy.
Warning: heavy SPOILERS ahead!
To me there were two main points in 'The Show':
1) First, that it is not ideas that change people, it is empathy, real people.
We see the story of a confused man who could not overcome the meaningless deaths he witnessed in the beginning of the movie. However, rather than trying to deal with it, understand how it affected him, he decides to teach the world a lesson, to change the world.
So he goes ahead with this 'reality show' where people kill themselves in front of camera as he wants to teach people the value of life and death, while he doesn't much understand it himself. He does so quite narrow mindedly, without being able to give people something truly meaningful, counting on that people would simply start appreciating life by seeing others die. Throughout the movie we see that his message does not reach people - they either watch the show for entertainment, routing for people to die, or they hate it and want it down. And they do not understand it because he does not - the show is based on his need to understand death rather than on empathy and knowledge.
2) The second idea I see is that it is life and love which create meaning and which are capable of changing people, not death, as the main character believes. We are introduced to this idea through the story of two secondary characters: the sister of the main character and a participant in the show whom we get to know throughout the movie.
The sister ends up killing herself in the show which deeply affects the main character. His sister was meaningful to him when she was alive, she was his last family. He needed her to stay alive because he loved her. Her death is supposed to make him understand that he should have looked for meaning in life, rather than in death.
The last participant in this show was a broken man who could not support his family. We are shown they have a pretty good relationship, although not perfect. He wants so much for them to have money that he is willing to die. However, in the last moment he realizes that he loves them too much, and is much more valuable to them alive, therefore does not go with his plan. Until this point the audience was shouting for people to off themselves, and this was the first time in the movie we actually see them routing for a participant to stay alive, supporting life rather than death. Which was, in the end, the idea of the host.
As a conclusion, I think this movie shows us that empathy, strength, and life are what really touches people and makes them route for life, not ideas and not death. The main character stopped his madness when he felt empathy for the first time in a while, and the audience changed when they felt empathy for the man who is willing to live and love.