Being gay in a homophobic place would have explained Sumner's encouragement of diversity, his sympathy for the underdog, and his empathy for minority points of view.
Incidentally, in one seminar we were asked to raise our hand if we had had at least one homosexual experience. Of us thirty or so students aged 14-18, nearly everyone raised their hand. It was a revelation for me, a real Kinsey report.
Mike