So we agree there is something wrong with the world.
Now, the thing regarding art was it tried to reinforce the best to the world.
Now it highlights the worst of it.
However, it is fair enough that one specific characteristic, be it technique or goal, can not define what art is. That would mean to say anything with the same characteristics would be art. And that is not true.
The thesis statement throughout the documentary is: something was not just lost, it was purposefully broken. And artists are not trying to express a renewal with the same good principles, but to say "bad and ugly are now good and beautiful".