However despicable religious "hate speech" may be, distinguishing it runs into the same problems as "indecent"/"obscene"/"adult content" distinctions. Her Majesty's government (note: in the UK, politicians take even less responsibility for legislation than ours do over here!) wants to broaden "hate" speech legislation to include religion, not "just" race and ethnicity. Leaving aside concerns, legitimate as they may be, expressed by prominent comedians on overbroad restrictions, one need only look at news coverage of the riots in Bradford in 1987. Rushdie's book was treated by some mullahs as anti-Islamic hate speech. Neither the book nor those assertions was a joke.
The problem with treating religion as a proper subject for hate-speech regulation is that unlike race, gender, and ethnicity, religion is itself inherently speech. Consider, for a moment, purported fellow human being Matthew Hale. Would his creed constitute hate speech? Probably so, under any reasonable definition; and probably rightly so. But that's an extreme case. How about a much closer one… like Martin Luther? In the context of his times, the "theses" nailed to the door of a church in Württemburg fit within most definitions of hate speech. Although they are more famous for their implicit (and explicit) accusations of corruption, and as the spark that ignited the Reformation and Counter-Reformation, they also include a number of theological assertions and attacks that also fall within a "reasonable" definition of religion-centered hate speech.
From his perspective, and from the modern American perspective, Luther was merely a dissident engaging in free expression. From that of the Catholic Church hierarchy, however…. All of which goes a long way toward demonstrating that "religious hate speech" is not a proper subject for legislation, because the distinguishing theological confrontation from hate speech depends on more than just "reasonable people can differ"; it depends upon differences and distinctions inherent in the nature of the act to be regulated, and entirely upon the preconceived notions of the individual trier(s) of fact.