Do you know anyone BUT atheists who think that the Old Testament Covenant still applies to how Christians should live today? Anyone? Anyone at all?
Yes, I think so. Those who still want (but dare not do so due to the current mere human laws) to live under the laws in Old Testament are called fundamental christians. And these people exist - to be found in a country called USA.
OK, seriously, whatever the bible says, human have worked out that killing our own children is not good for reproduction of the next generation! It is ONLY the cruelty of a christian's god would command such killing - be it said so in OT or NT. This god is evil to the extreme! Are christians believing in a different god - not the one in the OT?
[References: Mark 7:9-13, Exodus 21:15, 21;17, Leviticus 20:9, Deuteronomy 21:18-21]