That atheism is not rationally justified

[Ben Davis]

atheism, while it may not be false, is not rationally justified

This is the crux of the argument: theists looking to devalue the concept of atheism. This argument is nothing more than a poorly thought out marketing exercise based on the idea that 'you're just as bad as us!'.

because reason is inadequate to decide on the matter.

That assumes reason is the mechanism by which atheism is achieved, which is not necessarily the case. For example, if a person has never been introduced to the concept of theism, they would be an atheist by default. Also someone might be an atheist for entirely irrational reasons.

So I have 2 main problems with this argument:

1. it's one big red herring: it doesn't matter whether the position is rationally justifiable or not, it only matters that people don't buy what the theists are selling. Coercing your customers in to buying your product may be the way many religions have worked, historically but it's still a shitty way of doing business.

2. At the end of the day, it's nothing more than a surreptitious attempt to shift the burden of proof: "I don't have to provide justification for God, you have to justify why you don't automatically accept what I say!".