I'm thinking that the definitions of agnostic and atheist are a bit blurry in some cases.

To me an agnostic "I don't know that any gods exist"
To me a atheist "No gods exist"

Because that's what they believe, neither usually state it as facts. I could say that I believe a invisible unicorn exists, and you can't prove it doesn't exist. So I can believe in it all I like. If I start insisting that you have to put up decorations, call off events or work or start obeying my invisible unicorn's decrees regarding blue cupcakes being ILLEGAL and IMMORAL, then it starts infringing on that whole "Freedom of Religion" thing.

And I love debating the nuances and aspects of all of it. I have discussions I'd like to have with Christian believers, but most seem to wig out and fall back to "YOU HAVE NO FAITH" as soon as I try.