Tricky because it seems unclear how free the choice of religion is. Most people seem to assume the religion of their parents. I think few people as adults check out different religions, and pick one they find convincing. There are cases of people joining sects, but there often seems to be a lot of brainwashing and manipulation involved, even drugs - is that really freedom? You can not change by law what people believe anyway, so that discussion is moot. But when for example Creationism and Evolution theory are taught as equivalent or Evolution theory is even banned, it seems scandalous to me and a betrayal of the kids. And as I said, the belief is not just beneficial, a lot of people also suffer for it.
As for knowing about the existence of god: it’s true we can never be sure of anything, like we could all be living in a simulation, god could just have created the world with all out memories a millisecond ago, and what not. But there has never been any indication of the existence of a god, except for the claims of people. So I don’t think you can say believing in god is equal to not believing in god. To be extremely nitpicking I could say I am an agnostic because I acknowledge the possibilities as above (god could just be messing with us by not showing up, we live in a simulation, whatever). But ultimately, that is nonsense - for practical purposes I am an atheist, because the other probabilities are too unlikely. Personally, I would also reject a god that is so unfair to prove themselves to a select elite of people (priests?) and demands of the rest to believe the elite. Also, it would be nice if religious people would apply that same argument to themselves and acknowledge that they have no clue if god really exists.
Freedom of religion also has limits in the US, I suspect. You can not just sacrifice virgins every solstice just because your religion tells you so, for example. So there seem to be some higher principles than religion, even in the US. I could imagine fair chances for everyone is one of that principles, so all kids should have a fair shot at education (no Creationist nonsense…).
And even if you respect freedom of religion, that doesn’t mean you have to approve of other people’s choices.
Anyway, I don’t want to hijack your comment thread for this age old discussion. I commented initially hoping to clarify why some people might be anti-religion (not that I know everyone’s reasons, just guessing at some of them).