As children we didn't say that. We just did it as a joke. Reconstructing the joke in memory when I wrote that article, I used those words to explain what we did.
I happened not to have been indoctrinated into a religion. I was raised as a secular Jew, but I never took it seriously. At most, the upbringing showed me how religion is historically important to most people.
I agree that children shouldn't be indoctrinated, especially if the doctrines are anachronistic since that just prevents the child from fitting into society.
I agree also that we don't fulfill a cosmic purpose, and that naturalism implies there's no objective meaning of life. I've written dozens of articles on existentialism and cosmicism.
But there are still anomalies in nature, such as black holes and personhood. We're not just ordinary animals. We're at the forefront of the Anthropocene, and we may be life's executioners or a stage leading to a transhuman form of cybernetic godhood.