Clean and unclean are not arbitrary, and they are not a question of worth. They describe what something is built for, the order of creation.
Where the words come from
In Hebrew the words are tahor (clean) and tame (unclean). They are about belonging to an order and about purpose, not about dirt and not about moral worth. An animal is not evil when it is called unclean. It is built for something other than the plate.
Why it is often misunderstood
People read clean and unclean like tidy and dirty, or like good and evil. What is meant is rather the question: does it fit the order, what was it made for. The scavenger and the filter feeder are creation’s cleanup crew, built to take in what is dead and toxic. That is exactly why they are not on the menu. Their task is a different one.
What the Bible means
Leviticus 11 sorts the animals by how they are built and by their role in the cycle of life. In the New Covenant, Yeshua declares all foods clean (Mark 7:19), and Peter learns in his vision that no human being is to be called unclean (Acts 10). The binding law falls, the principle remains as voluntary wisdom.
Why that sets you free
No food makes you better or worse before God. There is no forbidden list binding you anymore. What remains is insight: creation is built with purpose, and it is worth living with its order. That is wisdom, not law.
In one sentence
Clean and unclean describe what a creature is built for, not its worth. In the New Covenant everything is clean, and the principle remains as free wisdom.
Further reading
Dietary Laws: Clean and unclean
The Pig: What it is really built for
Plain Words: Terms explained honestly