Some apologists for religion try to turn the arguments that non-believers use against belief around. (It’s a bit ironic, since they seem to legitimize that kind of arguments by doing that.)
One of those is turning around the request for proof. A lot of unbelievers feel that the claim that god or gods exists needs to be backed up by proof. Turning around that is: I know god/s exists, you proof that it/he/she/they do not! Unbelievers can get a bit annoyed by that trick, and respond with things like: extraordinary claims require extraordinary evidence etc., which is all right I guess, but with regard to basically unprovable claims I myself am normally not very inclined to go there.
For me it’s sufficient that certain religious claims are simply very improbable. For example: you will go to hell! Well, I can’t proof that I won’t, but it’s so very improbable that I literally don’t lose a second of sleep over it. Another category of religious claims is not only unprovable (either way) but also irrelevant. For example, a deity that is outside time and space and doesn’t interfere with the real world. So what? Irrelevant. Or viewing the universe as a whole as god. Also irrelevant.
To sum up, improbable claims that I can’t disprove won’t make me any less an atheist. In the same way, I cannot care about supernatural beings that don’t interact with with the world.¹
However, there is one point at which the ‘proof’ argument can get to me too. That is when believers claim special rights because they are religious. ‘I am religious, therefore you are not allowed to work on [Friday, Saturday, Sunday]’ - or things like that. If you want special rights because you believe in an otherwise undetectable entity, you better come up with good proof!
1. It turns out that there are some believers that think that a god is a better hypothetical explanation for the universe than, for example, super-string theory (or other versions of expansion theory, etc.). However, as long as such a god hypothesis remains unproven its relevance seems vanishingly small (its only use will be to give a class of believers the pleasant feeling of having a theory that in their mind is as credible as for example string-theory). Worse, there is still no way to connect such a theory to their specific god, belief system, morality, etc.