I suspect the original rationale is about preserving the longevity of the backdoor. If you blow a hole wide open that anyone can enter, it’s going to be found and shut down quickly.
If this hadn’t had the performance impact that brought it quickly to the surface, it’s possible that this would have lived quietly for a long time exactly because it’s not widely exploitable.
If this hadn’t had the performance impact that brought it quickly to the surface, it’s possible that this would have lived quietly for a long time exactly because it’s not widely exploitable.