Is it really fair to call these such algorithms "security through obscurity"?
By that logic, wouldn't real symmetric crypto also be considered the same, since it's still just math that similarly swaps the data with other bytes, based on an "obscured" password or key?
The obscured part was pretending the unlocker needs external information
I think you right, however they left all the right clues to decrypt it in days. You really don't want to do that.
I think it is fair, as all the released CDs are identical. So all the symmetric keys used to encrypt the data are also necessarily identical.