Literalism vs Allegory

This simple issue keeps coming up again and again with regards to the holy books. "The Bible/Torah/Koran aren't meant to be interpreted literally,"

What kinds of books are meant to be interpreted literally? Instruction manuals, science textbooks and history books.

What kinds of books are meant to be interpreted allegorically? Nursery rhymes, myths, poetry and fiction.

I think it matters a big deal if the holy book is literal or allegorical.

If you are religious and you consider your holy book to be allegorical then congratulations: you're almost an atheist because you've just tacitly admitted that your religious book isn't to be taken any more seriously than a work of fiction.

If you think that your holy book is literal then you really need to answer all of the historical, moral and scientific failings of your holy book.

I'm fascinated by how there are still Christians around at all today. The theory of evolution, the fossil record, the molecular biological data and the geological record all agree with each other: Adam and Eve, in the Garden of Eden, never existed. If they never existed then they could never have eaten the fruit of all knowledge of good and evil, and therefore there can be no original sin for Jesus to have died for. The end, Christianity has been debunked as a fraud.

If you are still Christian is it because you don't understand the sheer weight of scientific evidence against your religion and/or you do not even know what your religion is about? If there are other reasons for believing in Christianity consider that the religion is ultimately worthless to you if it isn't real/correct.

The situation is similar in Islam except whereas Christianity claims to be 'true', Islam puts more emphasis on being 'correct'. However, like the Bible is full of myth and superstition the Koran is full of horrors and crimes against humanity. The acts of Mohammed are morally indefensible and generally quite sick and degrading. If you wouldn't vote for the Nazis then why are you voting for Mohammed? There really isn't a big difference between those two ideologies.