Δαφνη Ευτυχια Αρθουρος

a) As far as I'm concerned, "religious liberty" includes freedom-from-religion. And I'm pretty sure that's the real point here in the first place.

b) What siderea said. Make it a "pro-something" statement instead of an "anti-something" one, and at the same time avoid looking like you're attacking the theocrats.

The Religious Right will, of course, still perceive this as an attack (or at least opposition), but you want the initial reaction of third parties to be that you're standing up for something positive, not picking a fight with a different group. (They'll notice that, but you want it to be the second thing they notice, not the first. Makes it easier for them to sympathize with you. Not phrasing it as anti-religion especially makes it easier to religious people who aren't trying to be pushy to get on board, like me.)

Note that this is why we have "pro-choice" and "pro-life" movements, instead of "pro-choice" and "anti-choice". And why anti-GBLT groups try to sell themselves as "pro-family-values" -- they want to be For something Positive. I should be able to toss out several more examples, but I'm blanking -- maybe someone who's gotten more sleep will do so.