I get he would have been disappointed. But he seems to have his head screwed on pretty well. He would have known, and was likely told in camp, that his time was coming. This was one small moment in a career that potentially lasts for 10+ years across multiple managers. If it was the thing that pushed him out it doesn't speak well to his commitment.
Side note, the idea that he would think there is too much ego, politics and dysfunction in the Aus setup, better go to Greek football where I will never be sidelined unfairly, seems a little naive.