"Any effort or attempt to break out of the Zen Hedonist thought system would be defeated by loss of ego, which formed the core of the doctrines."
I think that "ego" means a sense of separate selfhood? In this sense, I also think that ego has to be transcended because nothing is separate. Everything is interconnected and interdependent. This self, or individual subject of consciousness, is a transient manifestation and expression of the cosmic totality, like a wave of the sea.
However, ego is transcended by realizing interconnectedness, not by being caught in a thought system or a set of doctrines. Realization is approached by the practice of awareness, not by acceptance of the idea of "interconnectedness." I used to read, think and talk about Buddhism. Now I sit for meditation. No credit to me. I have been incredibly slow to start to understand what all the words have been pointing towards. Books on Zen are legs on a snake.