Futhermore, malnutrition - divided into a)protein deficiency, which is the biggest component, and b)micronutrient deficiency - is globally the most important risk factor for illness and death. Over 19% of young children in India have a protein deficiency[1] and over 41% of young children in rural Nigeria[2]. It's obviously worse in undeveloped nations but check the dead babies above if you think it can't happen in the developed world too.
These are tragic instances of children being underfed or, in the case of the 'vegan babies,' being fed very, very stupidly. Babies should be breastfed and children should get enough to eat. I don't think any mainstream or even oddball medical or dietary understanding is being challenged here.
(promulgating the myth that "complete proteins" are an important idea is still bothersome, but now I'm not sure that's what you were doing)
The issue I have is with the dietary trend of pairing foods in order to obtain a "complete protein," which is extremely silly. Dying because one of the amino acids is not represented in your diet is something that basically never happens to a well fed person (it would take an extreme example, and the internet can supply those, but...) so I have no issue with it one way or the other in a discussion about diet.
If by "well-fed" you mean getting enough total calories, you are still mistaken.
Kwashiorkor is the condition of not enough protein while actually getting "enough" total calories. What's more, low overall protein intake actually increase your need for essential aminos, due to the body synthesizing non-essentials from its supply of essentials.
There are also serious health effects (eventually leading to death) associated with deficiencies in specific essential aminos. Lysine deficiency is one. You only need 28mg a day but if you are eating mostly wheat it can happen.[1] If you are lysine deficient it comes with its own disorders and it also leads to micronutrient deficiency.
