Because I’m a nosy bastard, that’s why. I can’t leave anything alone. As soon as I spot a loose end I’m picking at that thing to see what unravels, and there are a lot of loose ends in theism.
Mum went through a Baptist phase for a while when I was young, so I certainly got the indoctrination, but I wasn’t what you’d call ideal convert material. Sunday school teachers really don’t react well to being informed by a 10 year old that the concept of manna violates the laws of physics (yes, I was that kind of kid and yes, I grew up to be a business analyst). I was one of nature’s science geeks from an early age, and therefore aware that many of the things I’d read in the Bible did not make sense. The older I got, the more I became aware that the Bible was written by someone with a very poor grasp of physics, biology and history. If all people were descended from Adam and Eve, how could there have been enough genetic diversity to produce a viable population? The earth is flat? Are you serious? If the Bible was really written by the Supreme Being it wouldn’t include such obvious rubbish. It simply wasn’t credible.
Ultimately, it wasn’t the logical flaws or the contradictions that really turned me off Christianity. It wasn’t even the ethical implications of a God who tortures sinners for eternity and allows children in famine zones to starve, although those factors were pretty important. It was a question of relevance. I was growing up in the late twentieth and early twenty-first centuries; Christian values weren’t the only set of values I was exposed to. Secular values espoused tolerance and equality, and were much more attractive to me than a culture that treated me like a second class citizen because I happen to have been born without a penis. Not wanting to be a second class citizen, I decided that Christianity could fuck right off.
Of course, Christianity is not the only religion out there. What about all those other brands of theism? I don’t find them any more plausible on a philosophical level, but more importantly I don’t need them. I can do my best to be a decent human being without any religion at all.