He's not treated well. Maybe compared other (inhuman) places, but he feels his treatment is so vindictive that he has tried getting the human rights court involved.
His protests as well as the treatment often perceived as "absurdly comfortable" all hinge on one fact: he is kept in permanent solitary confinement. Which is otherwise considered an additional (and harsh) punishment for regular prisoners. And it's the reason why he has his private gym and entertainment facilities, because those would normale be available as shared facilities to regular prisoners.