Malumba,

The question is whether the atheist is making a scientific claim for the non-existence of God/gods or merely stating their opinion.  If it's their opinion, it's a matter of faith or belief that God/gods don't exist, sometimes predicated on a scientifically based argument such as the one you propose here.  That's fine but it makes their position no more valid than the religious claim.  You use the scientific method only so far as it is convenient for you here, however.  Just because we cannot confirm the existence of God/gods does not mean He/they don't exist, nor would science make such a claim.  Science hypothesized the existence of the atom and quarks before we could discern their imprint on reality.  So, despite having no meaningful sense in which they can be said to exist, science did not deny their existence, it simply did not confirm it.  So too, with God/gods.  Not being able to materially discern the existence of God/gods doesn't negate God/gods, except to atheists.