"I will make them eat the flesh of their sons and daughters, and they will eat one another’s flesh because their enemies will press the siege so hard against them to destroy them."
This is another case of creative hermeneutics. The context makes its clear that this is a prophetic passage. God is declaring judgement against the Israelites for disobeying Him. The Babylonians will invade their land and besiege Jerusalem, cutting off their food supplies. They will resort to cannibalism.
Other references to cannibalism are found in Leviticus 26:29, Deuteronomy 28:53, 2 Kings 6:24-29, Lamentations 2:20, 4:10. Again, in context, these references are either declarations of judgement for disobedience, or descriptive. It should be absolutely clear to the reader that these passages are not prescriptive. As I have written on this blog before, you often learn what the Bible says by what it doesn't say.