I do focus here on Christianity, but I criticize all exoteric theistic religions. I have different objections to Buddhism, Taoism, and Hinduism, which I've written about. And in other articles I focus on Judaism and Islam, although most of my religion articles are about Christianity.
I'm interested in the broad outlines of an atheistic religion. My articles on pantheism, existentialism, cosmicism, transhumanism, enlightenment, and the promethean revolt have implications for some such religion, but I haven't focussed much on the details. Maybe I'll consider that question of an atheistic religion more directly soon. This other article of mine might come the closest so far (putting aside my older writings on my blog):