Idolatry vs. Atheism
Rabbi Israel Chait
Sera: Who errs less: an idolater or an atheist, and what is the reason?
Rabbi Chait: It depends on the type of atheist. If he believes that there is absolutely no God, i.e., there cannot be a God, then he is the furthest away [from truth]. But if he just doesn’t know the proof of God, but accepts the possibility of God, then the idolator is further away. This is because the idolater at least has some concept of a "cause" for the universe, as opposed to the absolute atheist.
Sera: The 10 commands are listed in a hierarchy of importance, most crucial to less crucial. This proves your point that recognizing God (atheism) is more crucial than idolatry, as the 1st command is to know God, and the second is to reject idolatry. Thus, denying God (atheism) is worse than idolatry.