Art is meant to be enjoyed and appreciated by individuals as they see fit, and while there are many positive attributes associated with postmodern art, my personal preference is for modern art. I love the right angles and clean lines associated with modernism, particularly as set out in modern style architecture.
With the world constantly changing modernism is really the only answer and way to go. We can't fight change and we are going to have to keep going with it. The modern way of doing things has increased profits for people, the amount of food we have, and the way people interact with each other. It keeps a more social standard going and less crime, even though it seems like there is more now, it is only because it is reported all the time.
If you were to compare the most famous of postmodernist art and classical art you would find that post modernist art is unrealistic and overly simplistic lacking real form. No, beauty is not merely subjective, beauty comes from emotional complexity and how it resonates with the viewer, but also from how well it replicates reality, and how it depicts the state of mind of te artist. Mere shock value doesn't make art "beautiful". A painting of single color has no depth and nothing to understand in it. It can not be considered "beautiful".