What is the Bible's Achilles Heel?

I read this on a recent Facebook post: "The achilles heel of the Bible is Exodus." What did this person mean by that statement? The following is a Wikipedia post on Achilles and his heel:

"Achilles' most notable feat during the Trojan War was the slaying of the Trojan hero Hector outside the gates of Troy. Although the death of Achilles is not presented in the Iliad, other sources concur that he was killed near the end of the Trojan War by Paris, who shot him in the heel with an arrow. Later legends (beginning with a poem by Statius in the 1st century AD) state that Achilles was invulnerable in all of his body except for his heel because, when his mother Thetis dipped him in the river Styx as an infant, she held him by one of his heels. Alluding to these legends, the term "Achilles heel" has come to mean a point of weakness, especially in someone or something with an otherwise strong constitution."

So, obviously, the Facebook comment was meant to say that you can bring down the Bible, just as Paris brought down Achilles, by attacking it through the book of Exodus. I replied that, in my opinion, the Bible has no Achilles Heel if Christians are willing to stop trying to defend it for what it never has professed to be. Exodus could certainly be the Achilles Heel to certain perspectives on the Bible because these perspectives claim absolute and totally accurate historicity of everything contained within the pages of the Bible.  Many religious groups and individual believers have backed themselves into a corner and have had to create "proofs" and provide "explanations" for claims that are indefensible. The Bible is not modern historiography nor a scientific textbook. To represent it as such is to misrepresent it. 

The Bible is a collection of writings, of various genres, which originated in the ancient Near East. These writings, collectively, were written over a vast period of time and were, individually, copied, edited, revised, recopied, transmitted, translated, etc., until they were brought together in "one" book as we now have it - though various religious groups have some different books in their canonized version than the one you probably possess. Even by the second century CE (i.e., AD), the Bible, as we have it today (in one of various collections/canons) as one volume, did not exist - all the individual writings existed (some of which existed in more than one version). Only by sometime in the second century CE did the Jews formalize the books that make up the Hebrew Bible - though the sect of the Samaritans would disagree with their canon. It was not until the fourth century CE that Christians brought the books together that make up our various modern Bibles.

The Achilles Heel of the Bible is not the Bible itself, but can be found among the dogmatic assertions that at least some religious groups and individuals make about the Bible, because it is often misrepresented as something it is not, could never have been, and never will be. But also, those who oppose the dogmatic assertions of the religious groups or individuals have their own Achilles Heel(s) because they often counter with dogmatic assertions of their own that are just as indefensible. We will touch on a number of these dogmatic assertions that misrepresent the biblical books individually, and the Bible collectively, as we continue our journey through the texts in 2018.

Recommendations for further reading: 
1. Ulrich, Eugene C. The Dead Sea Scrolls and the Origins of the Bible. Grand Rapids, MI: William B. Eerdmans Publishing, 1999. 
2. Dever, William G. What Did the Biblical Writers Know and When Did They Know It?: What Archaeology Can Tell Us About the Reality of Ancient Israel. Grand Rapids, MI: William B. Eerdmans Publishing, 2001.