I believe it is not possible to remove the Snapshot and Open Snapshot Library options when right click is performed on the object using security rules. Security Rules will disable the options from the navigation toolbar but not from the Right click operation.
However, based on the rule created, it will not give the user an option to use snapshots in their stories ,since the Story option is disabled.
This is not correct,
security rules ALLOW you to disable right click options, as you can see.
But if i disable the snapshot i can't create bookmark, I suppose this is a QS bug because these two funcionallity are defined by two different resource.objectType, resource.objectType = "snapshot" and resource.objectType = "bookmark".