When I first read my friend's post, I had a major "I notice that I am confused" moment, because it just seemed so implausible that someone who understood actual atheist arguments (as opposed to dead little sister Hollywood Atheism) could convert to religion, and Catholicism of all things.

Catholicism is actually one of the intellectually more formidable religions. If you accept a few key axioms of Christianity (and even most atheist Westerners do) and think about their implications for a lot of time it seems remarkable how vulnerable you are to converting to it.

In Christianspace, for the intelectual who likes playing around with very abstract dry concepts Catholicism seems to be a strong attractor. While protestants have played around with reversing its stupidity traditional Western civilization is fundamentally Catholic civilization. It gets the halo effect from a whole lot of art and great thinkers and pretty Churches. Then there is also the sheer majoritarian argument in its favour since it is by far the largest denomination and has institutional continuity going back more than 1500 years. When people around the world think Christianity, they think Catholic.

Also as Moldbug says:

Thomas Aquinas derived Catholicism from pure reason. John Rawls derived progressivism from pure reason. At least one of them must have made a mistake. Maybe they both did. Have you checked their work? One bad variable will bust your whole proof.