I'm of two minds on this.
On the one hand, laws prohibiting Holocaust denial are a violation of free speech. The hypocrisy of Judge Peters in giving asylum for a terrorist but not for people whose only "crime" was writing something, however false and horrible, is blatantly apparent.
On the other hand, I vehemently disagree with Holocaust denial and I also believe that the vast majority of Holocaust denial is not done in good faith. While what the British government is doing to Messrs. Sheppard and Whittle is unjust, I am unlikely to shed a tear over them.
Should we have asylumed them? While I am not inclined to say that we should have, they are likely no worse than other people we have asylumed in the past. Perhaps, then, that is the problem; not our unwillingness to asylum people in cases where the issue (free speech for genocide deniers) is politically incorrect, but our willingness to grant asylum when the issue is politically correct.
I would probably be okay with making overall asylum policy much tighter, provided it applied to everyone equally. It may sound selfish, but this is a British problem involving Brits on one side and Brits on the other, and I am not inclined to intervene directly. Definitely I don't feel a sense of owing anything to Messrs. Sheppard and Whittle.
Having said that, I would be much more disturbed if the U.S. adopted similar laws here, ironically enough for the old Martin Niemoller reason, that if we let them (i.e. the government) come for the unpopular, even the evil, in an unjust way, eventually they'll come for us as well. But having said that, I am not terribly inclined to try have us try to deal with other countries' problems on this front, unless of course, it involves the other country enforcing unjust laws against U.S. citizens or, to a lesser extent permanent residents.
That is all.