Pyrrho:
A god's existence does not need to be disproven. The fact there is no evidence for the existence of any god means we have no rational need to accept claims of their existence.
The idea of either proving or disproving the existence of deity is itself irrational. For what is proof or evidence of something that lives outside our observational parameters?
Proving there is a god is like asking a computer program to prove there is a programmer. It can show code in the computer just as we can show DNA. It can show organization where there is no right to be organization, as we can show with the order of the universe existing in spite of entropy.
But even more fundamentally, in every religion where God has appeared to Man literally (which would be a form of proof, at least to that man), God's word has been that faith precedes the miracle (or "proof"). The idea of the need for Faith in a spiritual development means that it is irrational to demand proof, just as it is irrational to demand someone show lack of proof.
Someone who has not planted his own seed cannot demand to see the flower before planting and caring for the seed. And in religious terminology, that same person will denounce other people's "flowers" (proof or evidence) as the product of delusion, as non-existent, or whatever because they have not planted their own seed and therefore cannot see the flower that has the potential to grow.
So promoting atheism by attempting to disprove religion is irrational, and so is attempting to demand proof before believing. Belief/faith and knowledge cannot coexist.