The Bible is one of the most influential works of human civilization and is thus worth reading independent of its truth. That said, actually reading it is the easiest route to atheism.
It is impossible to possess a properly functioning brain and endorse its contents in their entirety upon grasping them, since to do so would be to endorse a variety of mutually incompatible propositions:
M and J's hometown was Nazareth and it wasn't;
Jesus was born of a virgin and he wasn't;
he existed before birth and he didn't;
he cleansed the Temple in the first week of his ministry and he didn't;
the Kingdom of Heaven will be here on Earth and it won't be;
Paul thinks pagans are responsible for their non-belief and will be punished accordingly and he doesn't;
Paul converted Jews in Greece and he didn't;
Jesus was the Son and he wasn't (he was the Word, silly!);
Jesus cried out to God in confusion right before being executed and he didn't;
Jesus died on the day before Passover and he didn't;
Jesus' genealogy was as Luke describes it and it wasn't (it's also as Matthew described it, even though they are different!);
etc.
I don't know that most "believers" are even aware of how shot full of inconsistency and contradiction the text is. Anyone who takes it all as literally true hasn't read it, is an idiot, or both.
So, at best we can retreat to selectively choosing the bits we think are true, or emphasizing a "metaphorical" interpretation of things. If we do the former, we need independent justification for believing the selected bits ("the book says multiple, mutually incompatible things about why Jesus died but this one is really true, I swear!) -- none of which exist -- and if we do the latter, we are admitting the claims in the book aren't literally true, which is as good as saying that they are all false.
