The sacrifice of children in ancient cultures is on the surface not just pretty universal, but totally baffling.
Throughout history the dreams of men have been simple really: Let the harvest be bountiful. Let there be enough food so my family can survive the winter. Survival would seem to be the primary genetic motivation for the human race.
So why kill your own children? What is the logic there? Those hands for helping with the harvest. Those hearts to take care of their parents in old age. Those extra eyes and trigger fingers in case there are disputes with the neighbors. How could you lose that, -- on purpose? You might even argue that your children could be an ultimate meal if your survival was that threatened, but --- this option seems not to have been extant in human history, so that underlines their importance even more, and the weirdness, that they could be sacrificed.
It is like there is this leap going on,a leap beyond genetics, with the sacrifice of children. One thinks of leaps in history. The logic might be-- here is the precious thing I have, and I will surrender it...because.... ??
Other leaps are like the what Jan Cox called, "falling up the stairs," when he referred to man's ability for language manifesting itself. Manifesting like it was there all the time. Who knows about that. But suddenly we could talk.
Then there is what Karl Jaspers called the "axis time of history", when, simultaneously, in effect, a certain objective thought became apparent, Socrates. Buddha, Confucius, the composers of the Upanishads, Lao Tzu. There were other figures Jaspers mentioned. Of course the word he used was spiritual influence. You might also say a certain kind of personhood was involved. For my point here the significance is this leap humanity made as a whole. A leap which cannot be explained by "cultural diffusion," try as the positivists might to do so.
Back on the track: it may be that there was a time, between the birth of speech, and the birth of philosophy, when what men appreciated was, the existence of this leap, this gap, and all they could perceive was that a certain appeasement was called for, in the presence of this gap---
Only that's not really it, either. So I don't know an answer, yet. But I know this --- why these children were sacrificed is something we can understand, because we too are humans, and this is something that happened to our species. The standard reply, that they were barbarians, is I trust, an evasion that does not merit a response. There is an answer, I just don't know it.