Manage backup destinations>Delete recovery point does not delete files?

I have a simple maintenance question.  I wanted to properly delete a very old backup/restore point/image, whatever it is called.  It was an independent image of a PC drive with the image stored on a NAS.

I used SSR to go into advanced, right clicked the drive letter and found the restore point I wanted.  It matched the name, date, etc. of the one I wanted to delete.  I right clicked and chose delete, then chose yes.

It disappeared from the SSR lists but the backup files are still there on the NAS.  So I deleted manually....but I would have thought SSR have deleted the files but perhaps this is a safety feature.

Thanks,

BJB