This questions stems from the MSDN page on LinkedList under "Remarks" (fifth line).
Lists that contain reference types perform better when a node and its value are created at the same time. LinkedList accepts null as a valid Value property for reference types and allows duplicate values.
I have searched through the source code and nothing really stands out to me. Could it be that this line was once true but was just forgotten about? If not, then why is it the case?