I guess from a certain point of view you're right, a credit score is a list of all the debts you've had an how you've paid them back.

So somebody with no debt is "unknown", rather than the expected "good".

In Finland we don't have credit scores, instead we allow looking up defaults. Which seems like a reasonably sane approach - known-bad borrowers find it hard to repeat that behaviour, and somebody with no history of taking loans/debts isn't penalized.