Here is article to which I think we should write rebuttal.
Anybody can contribute to this rebuttal by posting his opinion and links to studies. I will edit this message by adding your opinion, please correct me if you found any errors or mistake, or if something can be rephrased to sound better (I’m not native English speaker)
Taking additional amounts of vitamin B12 is recommended by almost all vegan books. Also vitamin B12 is produced by bacteria and is available in supplements
Also please provide links to other rebuttals if exists.