The purpose of art has never been to entertain, even if art can be entertaining. The fact that so many people think such a decadent idea shows how debased our society has become by way of the profit motive.
This is an insane way to think about art. Of course art exists that entertains, and it is art. To say that art can't entertain is an absolutely drab way to look at things - it almost assumes that only negative emotions can be transferred through art.
Had any of the examples been Lessons of Darkness or Grizzly Man or Burden of Dreams, this conversation would have gone quite differently, but since none of those films were released on Youtube they were not even an option to begin with.