Ego. Ok also union busting but largely ego. Around the same time one of his children who happens to be trans from his first wife (who also publicly denounced him) publicly disowned him and his long term on again off again partner left him for a short lived fling with Chelsea Manning, a trans woman famous for going to prison for leaking human rights abuses by the military in the Iraq war. And around that time democrats started getting anti billionaire talking points going very mainstream. And so he began courting the right. He was already addicted to twitter and he found himself deep in the alt right pipeline.