'5 billion people' was just snark that highlighted the fact that the vast majority of people don't believe we're alone or got here by random chance, whatever your interpretation of that is. Atheism is, to me, a knee-jerk reaction to spirituality/theism more often than not. To me, it's the denial or refusal to see the inherent structure, patterns and symmetry throughout life and discern any larger meaning. To me, that's just nihilistic and comes from an egotistical fear of relinquishing control over one's own destiny. But that's just my opinion, you've got yours. People can believe what they like, and I can mock it too cuz free speech and stuff
And I'd disagree that everything is fair game, there are clearly evil and negative belief structures out there with ill intent for humanity, and people who worship negative entities who do terrible things in their name, both knowingly and unknowingly.