That code would almost certainly crash if run against Wine's wmvcore.dll. It is just to have a piece of physical evidence that there IS a way to access the DRM interfaces. It would of course be removed, once the mechanism by which DRM interfaces are exposed is understood, and Wine implements the corresponding functionality.
Applications normally access this by being linked with a lib called wmdrmstub.lib access to which is restricted by Microsoft, instead of with the wmvcore.lib that anybody can get. I do not know what the differences are between those libs, e.g. how WMCreateReader comes to produce a reader that exposes a IWMDRMReader interface when you link with one but not the other.