The policy that spawned Smith's short list was announced in August 2005 -- after the infamous 7/7 London terrorist bombings that left 52 dead. In that spirit, Smith was right to bar Samir Kantar, a Hezbollah militant who served 30 years in prison for his part in the killing of an Israeli man and his 4-year-old daughter, and other dangerous extremists.
Savage simply is not in that league. He may offend some folk, but he does not draw blood. In 2008, the Brown government expanded the 2005 law to block the entry of those who would "stir up hatred within our society." There is a problem there: If the Brown government wants to keep out angry Americans, then the list isn't nearly long enough.
And there is no getting around the suspicion that a Labour pol decided to use the big club of government to bully a conservative Yank just because she could. Like the porn films, the act may have made the Smith household feel aroused, but it wasn't particularly helpful to the British public.