This is true of any good composer like Penderecki. The music is full of humor and irony. The main point in this piece is the C major chord, and how he toys with it. But you can't appreciate this unless you know the music very well. So this piece contains inside jokes for musicians, or at least for those who know the score.
Music is written for a variety of reasons and various audiences.
What matters is your personal experience of the piece. Do you think that contemporary music has the same goals as earlier music, like a Beethoven Sonata. Tastes have changed and certain rules have changed, but the same artistic goals apply. We still have form, phrases, structural points of arrival, development of certain motives, musical fragments, sounds, moods, and so on. To me there's no difference between Beethoven's work and the music of our time.