@Pied_Pfeffer Okay, My pathway to atheism is very very long, but I’ll try to cut it short as short as possible:
1. Despite the fact that both my grandfather and father were atheists (my mom never expressed a preference although she did convert), I believed in God all my young life, certainly through my Bar Mitzvah. In high school, I began studying and taking classes with a renowned Theosophist who studied under some of the major Theosophical thinkers of the early 20th century. When I took seminars from him, I began to realize that there were different ways of looking at the world, and as a result I started reading about other religions. In summer school I took a comparative religion class in a local community college (some high school kids fuck off in the summer, I went to school—that’s how I roll), and read texts from many different religions.
When I went to college, I began to realize that none of them were “right” and I became more of a benign deist than anything else. I was (and still am) Jewish, but my belief in God somewhat fizzled into more of something like The Force in Star Wars. This was my New Age period.
That got crushed as I became more wrapped up in to day to day stuff of surviving as an undergrad, and later a medical student and resident. But I still believed in some sort of spirit force, Gaia, or whatever.
Then about 15 years ago, I really took quite a sudden and sharp turn into empiricism, and it was about the same time I discovered the Skeptical movement (which I have since distanced myself from for completely different reasons). The Skeptical movement was all about evidence, science, and even more importantly Bayesian statistical theory, and when I started reading and studying more about this, it clicked home. This was me. And it was inevitable that atheism would follow. It was like the final puzzle piece clicked into place and I was whole.
2. I know quite a bit about many of the more common religions. I obviously know a lot about Judaism and the various sects of Christianity. Less so about Islam. I know about Hinduism, Taoism, Jainism, Sufism, Buddhism, and Baha’i as I’ve either studied or been exposed to them. There are others too.
3. You don’t need to have a knowledge of religion to reject the notion of God. Your question implies that if you know just one religion, and you reject it, how can you know another religion is not correct? The answer is that it doesn’t matter. I am an atheist not because I’ve been exposed to a crap ton of different religions. I am an atheist because the notion of God makes no sense in an empiric scientific Bayesian sense.