The biblical God cannot do anything which contradicts what being God means. The story of Abraham’s near-sacrifice of Isaac tells us that demanding child sacrifice would contradict what being God means. We abhor child sacrifice partially because this difficult story is in the Bible.
If people react negatively to this story, you can initiate a discussion about today’s more hidden child sacrifice (for example, partial-birth abortion, child prostitution, exploitation of children for work or military purposes, etc.).
The fact that all these are done in the name of someone’s freedom (not the child’s!) does not legitimate any of them.