Because religion is laughable

Not Feeling Very Bright Today?

Atheist creationist Noah's ark meme picture - Not feeling very bright today?
Atheist creationist Noah's ark meme picture - Not feeling very bright today? Smile and remember... there are grown adults who actually believe that two penguins walked all the way from Antarctica to the middle east to get aboard an ark built by a 500 year old man.
There is simple rule of thumb when reading the Bible: take the text at face value, unless there's an obvious reason not to.  But this 'unless' is where the problems start.

Sometimes, like with Psalms, the language is clearly intended to be poetic, so not everything being said actually means what you think. For example, the psalmist doesn't actually think the earth has four corners.  Well actually, he probably does, but being divinely inspired, he doesn't really.  Well God doesn't. Anyway, I digress...

Then we have Prophecy, also known as poetry on drugs, where the writing can be full of very strange imagery.  Taking anything literally in the prophetic chapters is a risky move indeed, as we have seen with the numerous failed End of World pronouncements.

However, most of the rest of the Bible certainly reads like it was intended as historical narrative, and for the most part seems to correctly coincide with known historical events (miracles aside).

But this makes the Genesis account a real problem. It reads like the rest, and there is no literary reason to take Genesis at anything but face value.  In fact, both Jesus and Paul refer to it as such.

However, the facts clearly clash quite badly with generally accepted observed scientific evidence, leaving the Bible student with two equally unpalatable options: (i) use the metaphor wildcard and don't worry about the Jesus-Paul references, which is not good, because, well, Jesus and Paul; or (ii) you become a Creationist and fight the scientific evidence to the death, i.e. you become a complete idiot.