Genesis 19

The Most Objectionable Story in Scripture.

I asked a few people to explain this passage. I only ever found an answer that was – to me – expected and too simple: "This story exists to provide evidence of the state of Israel during its darkest times and to point to its need for a Savior." I don't think this answer addresses the question. The question is really, why is this amount of detail is included. There are plenty of passages that have a similar effect but omit the specifics. For example, Judges 12:1-16 (same book, only seven chapters earlier) ends with a civil war in which  42,000 Ephraimites were killed. (You will want to remember that, because it comes up later.) The cause of the civil war was merely that the Ephraimites asked Jepththah why he fought the Ammonites without calling them. Slaying 42,000 Ephraimites seems like a disproportional response, don't you think? It seems like some detail, something political, perhaps, may have been left out. But in Judges 20, when 25,000 Benjamites were slayed, the battle was clearly spurred by the outrage incited by the twelve pieces of the concubine that had been sent across Israel. Ultimately, what my question boils down to is: what is it about this particular event that requires a level of detail that similar stories omit?  If I take Luke 24 literally, then it must be that this story of rape somehow points to Christ in a way that is so significant, it cannot be omitted. I need only to figure out why.