First of all, it isn't clear whether by vegetarian they actually mean vegan. They repeat that this or that isn't available in plant based products and only animal products. It seems to assume vegetarians don't eat dairy which probably is a false assumption for most vegetarians.
Secondly with the deteriorating quality of farmed meat with the increased hormones, Antibiotics and other toxic chemicals, the health proposition of being a meat eater for the vast majority that don't eat naturally raised livestock has changed dramatically vis a vis vegetarians.
I've been able to drop 5 meds and dramatically improve my health by going vegetarian FWIW.