Its not so much that you choose not to run your life in such a matter but it is completely impossible for you to do so since a vast majority of "truths" one runs one's life from are beyond one's capacity to verify.
The only real question is why atheists insist otherwise on a question of god
Also because atheists are not part of a theistic community; atheists are categorically excluded from theistic community.
If one hasn't been born or otherwise accepted into a theistic group, then how could one possibly meaningfully and with proper justification take up their discourse and practices?
Unless one has a personal, direct revelation from God, how can one possibly be a theist while not a member of a theistic community?