No, because assuming existence isn't the null hypothesis. Not assuming existence is the same as not taking a stance. Assuming existence is taking a stance, it is holding a belief.
Only if you base your belief system out of science, which we've already pointed out is not a necessary standard (especially since you yourself do not base all of your beliefs in science).
Assuming nonexistence is also taking a stance and holding a belief, and it is a belief about which you are clearly fervent. If this were an experiment with a drug, the null hypothesis would be inconclusive or no effect, and the hypothesis would seek a positive or
negative correlation. You have taken a negative correlation (no existence) and vitriolically made it a conclusive statement by way of the "null" hypothesis. That's bad science. Your null hypothesis should be no impact (or no statement on God's existence or nonexistence). It's also worth noting that if a study comes back in favor the null, it comes back as "failed to reject the null hypothesis," not as "evidence for the acceptance of the null hypothesis." Even if "no God" is the null, lack of evidence simply fails to reject it, it does not support it as the alternative.