If I recall, Notch is also deeply depressed and probably has a fair bit of self loathing.
Still, as someone who also suffers from anxiety and depression big time, Notch's road is way more bitter, darker and dumber to be only attributed to depression. He built a halo of victimization around him. And like you said, instead of using his wealth for meaningful contribution or simply make his life better, he took some castle in LA and decided to become a sad little man on twitter, parroting hurtful nonsense. It saddens me really and I hope he can find a better road in the future that doesn't lead to so much bitterness