Nintendork :
Sure, strong commitment to security then it deletes your personal data for the lulz on a broken OS.
A single bug does not a broken OS make. 10 is a good OS that runs fine. The bug affected a minimal amount of people and was not being actively pushed to unaware users, meaning these people all manually started the update. Microsoft pulled the update before major damage to a much larger populace happened and as well it probably would not have affected the vast majority since the vast majority do not know how or use redirected folders.
derekullo :
If some one gains write access to your registry aren't you already pwned?
Needing the user to install an infected program to then edit the registry just sounds like every other virus/trojan out there.
Am I missing something?
No you are not missing anything. This requires quite a few things to be in play. Either they have physical access to the system and can crack or know the users password or they have to have the user install a program that gives them administrator rights to the registry. In a typical business environment the user normally should not be an administrator. Even in a personal environment the user should be a power user with a admin account they have to allow installs to happen.
It actually sounds like a meh vulnerability. Microsoft should patch it but it is not something that I would worry about too much unless you have hackers walking around your office/house daily.