but I don't understand why he's completely giving up aviation.
Perhaps he was so utterly pi55ed off by burdensome regulation which although it had nothing whatever to do with his working life, none the less threatened to remove his livelihood, that he felt it necessary to make this (futile) gesture of disgust against the establishment.
Many pilots fly perfectly safely and legally by declaring themselves medically fit without any medical examination necessary (Medically related NPPL statistics are I understand better than Class 2 ones) Moves are afoot in the USA for further relaxation on medical matters, and of course what motive might anyone have for intentionally infringing?
Edit. I know nothing of the circumstances of this case and the whole episode was undoubtedly a complete debacle from any point of view.