This is an old myth (much like raising the iron concentration in your blood via spinach).
Milk actually
depletes the calcium from your bones.
https://saveourbones.com/osteoporosis-milk-myth/
Not saying it isn't related at all, but B12 deficiency is often rather the result of problems with the digestive system.
I've had my blood checked last year and many 8-10 year long vegans I know do regular blood tests and they usually have no deficiencies, probably because they have a healthier life-style (no driving around in cars, more movement and some regular but not extreme sport) and probably also a more varied diet as in not only a handful of different ingredients unlike most omni/vegetarian/vegan people in general.
Although I do take B12 supplement just to be on the safe side.
Here's some more detailed information on the topic which isn't propaganda for either side and is linked to from vegans as well as anti-vegans sometimes:
https://veganhealth.org/vitamin-b12/
Now the article by Mr. Vivian Goldschmidt MA you linked lists two studies from 1994/1997 as it's source.
First one is this
https://www.ncbi.nlm.nih.gov/pubmed...actures+in+women:+a+12-year+prospective+study
This study included only women. The most important cause of osteoporosis in women is not dietary deficiency but it is lack of estrogen after menopause. So obviously the study concluded that higher consumption of milk or other sources of calcium did not prevent osteoporosis in old age.
This is the second article
https://www.ncbi.nlm.nih.gov/pubmed/8154473
This one is actually small study with only 209 cases of hip fractures in patient above 65 year age. They were asked questions about their lifestyle at the age of 20. And conclusion was that consumption of dairy products at the age of 20 increased risk of hip fracture after 65 year age.
This study design is real surprise for multiple reasons. 1.) 27% of the history was obtained from proxy respondents, 2) what is the correlation of dairy product consumption at age of 20 with hip fractures after age of 65, what about diet from 20 to 65 years. 3) how many will have good memory of their diet history before 45 years even when proxy respondents are not used. 4) Author of this study themselves writes that results were unanticipated and needs to be confirmed by other studies.
What Mr. Vivian Goldschmidt has written in saveourbones.com goes much beyond what this studied had said. He seems to have used plenty of imagination and ignored all the newer studies. ( you can search for yourself on pubmed) to brainwash susceptible audience.
[doublepost=1570540105,1570539575][/doublepost]About B12, it is practically not available in vegetable kingdom, so only sources of Vit. B12 are animal products, and for vegans it is Milk and dairy products. However excluding strict vegetarians (not using dairy products), B12 deficiency is usually caused by digestive problems, as Vit. B12 has very complicated intestinal absorption.
About your comment on iron and spinach. Bioavailability of iron from vegetable sources is low as iron in these sources is in ferric form ( not ferrous )+ there are inhibitors like tannins/phytates in veg. diet that inhibits iron absorption. But still people taking good vegetable diet, can maintain iron concentration without supplements. So spinach is not bad iron source at all.
Just to add some weight to about text, I happen to be MD (Pathologist), and if you need I can provide references from standard text/articles for all I have written.