Is it just me, or does that bible account seem eerily similar to the account of the men surrounding Lot's house wanting to rape the angels? It has been said by one bible expert that this story is actually a bit of false propaganda designed to paint the people in that area as being as vile as the Sodomites, thus the story was deliberately written to mimic the account with Lot.
It has also been said that the story of Lot's daughters drunking him and raping him is also a bit of propaganda designed to tarnish the image of the Moabites and the Ammonites - the nations supposedly born out of the incestuous relations mentioned in the account. This seems to make sense as such an account provides no real spiritual benefit at all. I can think of no reason why such sordid details of how the Moabites and Ammonites came into being is of any spiritual benefit. It only makes sense to share such info if the motive is the tarnish the image of those nations.