Smart class parameters are not deleted when a puppetclass is deleted, they are kept as historical records.
Each delete and import of the puppetclass will cause more disconnected records of it's parameters.
Currently they are not in use since they can't be connected to the same puppetclass again and can only be manually copied to the new parameters.
This creates duplication of orphaned smart class parameters in the index.
Hiding them will still allow to access the data in case of an accidental delete but will clear up the orphaned records from the index page.