Technically, Cozo is using something called "Datalog with stratified negation, stratified aggregation, and function symbols", allowing aggregations to be auto-r

Technically, Cozo is using something called "Datalog with stratified negation, stratified aggregation, and function symbols", allowing aggregations to be auto-recursive when they form a semi-lattice, together with built-in algorithms which are black boxes taking in relations and giving you back another relation. Your example is taken care of by the "stratified negation" part. I believe "Datalog with function symbols" is already Turing complete, but you are right, what they call "Datalog" without any qualification in academic papers is not.