I dont care what an adult eats because thats solely his choice, but I do think that a growing child would need vitamins and protein from meat. The process of growing up is difficult and your body really needs the right amount of ingredients. Sure, you can take supplements but the body binds vitamins and protein with food way easier.
All the people saying veganism is the healthiest choice: please look at Japan which has the longest life expectancy and people there eat A LOT of fish products.
Apart from some fatty acids which most of the people get via supplements anyway, a well sustained vegan diet contains all the required proteins, vitamins and micronutrients anyone would need :/
Bashing it for that (at least to me) sounds pretty naive and plain childish.
As for Japan, i'm pretty sure it's not the amount of fish consumed that correlates with life expectancy.
For an adult, yes, but a growing person would need more energy and vitamins and other important ingredients for growing up. Unfortunately a lot of children don't do research on that. Vegans would have to eat more than people who also consume meat (their food has less energy) but kids don't usually eat a lot.
I don't have anything against a well inforned and researched teen who is a vegan, but I do say its darn difficult to keep up that diet and get all the ingredients and energy on a daily basis from vegan food (from my point of the view).
Obv people in Japan don't live longer because of simply eating fish, but apart from their lifestyle, the diet plays a big role there.
I haven't really noticed any bashing about vegans, mostly (constructive) criticism and overall theyre criticized for some of them seeking attention. If thats their way of "saving the world" then really... I don't come telling them to eat meat and why should they tell me to eat plants.