He explains why he thinks this is a good thing: the non-copyleft licenses allow producing non-free software, and he doesn't think they're doing a bad thing by a

He explains why he thinks this is a good thing: the non-copyleft licenses allow producing non-free software, and he doesn't think they're doing a bad thing by allowing this, just weaker. So if non-copyleft isn't ethically wrong, then selling exceptions isn't wrong either.