Yeah they water it down. It's the end of Leviticus (?) where God speaks of a soul devoted to destruction cannot be ransomed. So - yes the early Jews practised human sacrifice just like other people's. Abraham finding a ram caught by its horns in a bush is echoed in Mesapotamian myth, and is prolly just a parable about why human sacrifice, other than babies in Canaan stopped.
In the accounts, it is interesting to note that Abraham objects to killing entire cities, but does not demurr when asked to butcher his child.