To give SEP a bit of credit, note that the version of SEP run was the Unmanaged one (note that at 0:44 of the video the setting for "Symantec early launch anti-malware" is locked). The Managed version would have Admin Policies that can be utilized to prevent stuff like this (as long as the Administrator isn't a dope!).
But aside from this malware the Unmanaged version also leaves a bit to be desired against other scriptors, like VBS ransoms and Worms in general.