At line 15 of class System.Data.Entity.Utilities.ValidationContextExtensions.cs, you are using the property Name instead of calling the method GetName to get a localized string of the display name. This means that the ResourceType of the DisplayAttribute is ignored and will return the name of the resource instead of the localized resource.
Now: var displayName = displayAttribute == null ? null : displayAttribute.Name;
Should be: var displayName = displayAttribute == null ? null : displayAttribute.GetName();
Now: var displayName = displayAttribute == null ? null : displayAttribute.Name;
Should be: var displayName = displayAttribute == null ? null : displayAttribute.GetName();