My own personal opinion on this question is that while I don't believe in god, I am not anti-theist per se. I honestly and wholeheartedly think that there is no creator deity that we know culturally as 'god' - to me, such a concept is simply absurd.
None of this makes me an 'anti-theist'. That would suggest that I am against a privately, personally held belief in god. What rational, free-speech advocate would claim to be an 'anti-theist'? If someone believes in a supreme creator deity, who am I to say they're wrong? By the same token, if someone were to proclaim they believe in fairies at the bottom of their garden, who am I to say they're wrong? Their belief in such things is their own personal choice. The lack of any physical or logical proofs are no barrier to delusions. And that's fine as far as I'm concerned.
However, when personal choice and superstition starts to influence concepts such as freedom of speech then no longer am I so lenient in my language and tone.
We have a problem - religious beliefs (that venerate murder) are, on the surface, benign, but once they reach a critical mass in a community, they become controlling paradigms which one transgresses at ones own personal risk.