Just addressing the first part:
Because B12 is critical for life and isn’t found in any amount in plants (except some types of algae), it is by far the most important nutrient that vegans must be concerned with.
TRUE. Take your B12 supplement kids!
Animal protein contains all the essential amino acids in the right ratios. It is important for muscle mass and bone health, to name a few. Vegans don’t get any animal protein, which can have negative effects on body composition (2, 3, 4, 5).
The operative words being 'can have.'
Creatine helps form an energy reservoir in cells. Studies show that vegetarians are deficient in creatine, which has harmful effects on muscle and brain function (6, 7,
Creatine is produced by the body when needed.
Carnosine is protective against various degenerative processes in the body and may protect against aging. It is found only in animal foods (9, 10, 11).
Carnosine is produced by the body when needed.
Docosahexaenoic Acid (DHA) is the most active form of Omega-3 fatty acids in the body and primarily found in animal foods. The plant form of Omega-3s, ALA, is inefficiently converted to DHA in the body (12, 13, 14).
TRUE. I think a DHA supplement is good to be safe, but I also think most people will be fine with daily flax/chia in their diet.
Two other nutrients that have been demonized by vegan proponents are saturated fat and cholesterol.
Cholesterol is a crucial molecule in the body and is part of every cell membrane. It is also used to make steroid hormones like testosterone. Studies show that saturated fat intake correlates with increased testosterone levels (15).
Cholesterol is produced by the body when needed.
Testosterone is produced by the body when needed.
The article seems to confuse 'healthy' with 'optimal for muscle building at the expense of all else.'