I would also ask for some direct reference to how other religions were insulted. For context purposes, I was a B.A. student in religious studies at a secular college, and I don't see how in any way stating that a discussion of Genesis' creation account according to scriptural passages is one to be done within the reason of those who accept such authority. It's really no stretch. I'm also not stating that even those who are not within such a framework should be purged from responding. Honestly, one must remove some negative presuppositions and analyze the points I made in my previous post.
My initial response answers the individuals' question, namely being why we should accept Genesis as literal history on the basis of inner biblical evidence. If you reject the bible as a starting point, well it's nothing insulting to say that would be the totality if potential contribution.