Were you aware that sacrifice of firstborn children was part of the religious practices of ancient Israel, as of the surrounding nations? How do you feel about that?
Yes, but I still find it very striking to be reminded just how matter of course the practice would have seemed.

The stories about human sacrifice made Marcion so queasy that he suggested we ditch such passages from our Scriptures. Do you feel any sympathy for Marcion’s position? Why would you want to exclude stories of human sacrifice?
The inclination of cultures to remove stories of human sacrifice from our heritage is not unlike the inclination of individuals to remain silent about certain unflattering stories from their youth in which they behaved rather inappropriately in comparison to what they now consider to be properly decorous. I’m quite sympathetic to people (groups or individuals) who don’t what to look too closely at all the missteps they took along the way to becoming who they are.

What value is there in including them?
If rituals of human sacrifice are mimetic reverberations of the spontaneous scapegoating episodes that lie at the origin of every human culture, then including these stories in scripture has the value of directing people towards the truth of how we became people. It’s one thing stop telling the stories of debauched rabble-rousing that marked my youth because I simply am not that person anymore; it’s quite another for my brother and I to just stop talking about the results of our genetic tests once we notice that we only seem to share about half the same DNA. In the latter case, I can’t just say, “Oh that online genetic testing was just a quirky gift-giving thing we did for the holidays last year—there is nothing to talk about now”—even if I might be tempted to hide my head in the sand and convince myself that concealment (or “lack of candor”) might make it easier for everyone to carry on as before.

If human sacrifice is simply something some of our unruly ancestors dabbled in, then our scriptures wouldn’t lose all that much if those episodes were edited out. If human sacrifice is directly linked to the moment of hominization, then it is not an accident of ancestry that these episodes appears prominently in scripture. They mustn’t be ignored, if we don’t wish to remain ignorant.