They've forgotten about it. They aren't trained in it.
All that went before, that was common knowledge, has been forgotten.
It appears that they have extracted some of the bits from the original research and findings. The bits they like, I'm presuming!
So, they think b12 deficiency is easily treated (which the blood abnormalities are - and Murphy and Minot proved this back in 1926) but they forgot about the neurological and psychological damage.
Seriously.
You cannot actually believe what has happened until you've walked the walk.
And when you have, you see them attributing symptoms to other illnesses. And, since b12 is essentially to all parts of the body, you can only imagine how many other illnesses are being 'established.'
Speak to anybody today: friend, doctor, neurologist - anybody and 99 times out of a 100 they will describe b12 as 'just a vitamin.'
Yet this is vitamin is essential to life and if, for whatever reason, you aren't getting enough, you will start to 'misfire' either physically or mentallly. Or both.