They'd run all these tests on him and decided he wasn't racist. He wasn't, either, but not because he thought about it particularly. He just couldn't see the point. It just made for a lot of hassle, being that way, so why be that way? Nobody was going to go back and live where they lived before, were they, and if they did (he vaguely suspected) there wouldn't be any Mongolian barbecue and maybe we'd all be listening to Pentecostal Metal and anyway the President was black.