The biblical god is very evil. His precepts caused a lot of pain suffering and misery which are the very things precepts are supposed to prevent. It perpetuated cruelty unfairness and a lot of other bad things. There is no way that the biblical god exists because its all too obvious that humans with flawed logic and morals wrote the bible. We look back and see what religion has caused and i have no idea why one would think that in this day and age its a good thing when they are all written by men. If i were to slap you every time i saw you you would eventually start putting your hands up to keep from getting slapped. So why when god "slaps" us with lies do we still believe his new lies are true? Its ridiculous and religious people are completely irrational. They believe god is perfect. They also believe god gave us thousands of religions with one true one making you basically play the lottery for salvation.
Even Christ said, by their fruits you shall know them.
If you look at the dogma, you look at scripture, you look at the actions of the different religious organizations, and find them disagreeable, by that one admonition of christ, you should note that they are not the true faith, if one even exists. Pretty straightforward.
So yeah, I find the idea of reams of writings that are in direct conflict with simple observations about the universe to be a perfectly valid reason to rebuke the church.
I find the inconsistency of the stories, and the barbaric nature of many of its tenets to be a perfectly reasonable substantiation for my lack of faith in scripture.
The bible's claim to authority is based on itself. It is true because it says it is true. It also says that it is perfect and divinely inspired, implying that it should be of far higher quality than it seems to be at even rudimentary glance. That kind of makes leaving the faith an easy move, when you really get down to it.
Also, the nonsensical nature of an all powerful, all knowing being, condemning people to leave paradise and suffer because they did wrong before they ate of the tree of knowledge of good and evil, thereby not being able to know it was wrong, to be nonsensical. Especially since, being all knowing, that god knew they would do it.
As well, the idea that an all powerful being would need to sacrifice an incarnation of himself to himself to allow him to forgive people is downright inane.
If the book is not dependable, why have confidence in it? Why believe its claims? What other reason would a person need to turn their back on it?