"It's entirely appalling. Just shy of an atrocity." Which means he really is happy for them and their collective and complementary madness. "I try not to let it be too unsatisfying."

Sebastian makes a valiant effort to be a legitimately Good Person. It doesn't always go as planned, but he wants it very much. For a while, he wanted to live a quiet, uninteresting life as well as a good one, but that bit of nonsense has been pushed to the side.