Therein lies the great fallacy of atheism. You tell me the Universe is not guided by reason because it can be explained by reason. You say our existence is merely part of a system which follows logic, and therefore the system has no logic.
It seems reprehensible to suggest someone’s life doesn’t matter—but this is an objective fact about atheism. They’ll be the first to tell you that life has no meaning, or some platitude about how we must find our own meaning. Sorry atheists, life does have meaning and serves as much function to God as a brain cell serves to the mind; in this analogy, atheism is cancer.