It's bullshit straight out of the PETA handbook, where they blindly look past issues like nutrition. Livestock animals are highly efficient at turning carbohydrates, especially inedible ones to humans, into proteins and fats. It also ignores how hard it is to have a balanced vegetarian diet, let alone vegan (almost impossible), and the associated over eating required to hit essential amino acids, etc. Last I checked I'm not a ruminant, if I eat grass I throw up like a dog.
They also turn a blind eye to 92% of vegans being vitamin b12 deficient (low rates mean forgetfullness, high deficiency means irreperable brain damage) because only animals synthesise it. Same with Carnosine, which may protect brain tissue and prevent protein crosslinking. Also vitamin D3, which is derived from animal tissue, is much more effective at its job than D2, which is derived from plants, which vitamin D is linked with protection in a whole host of cancers and other issues.
Most arguments for eliminating meat consumption are wholly predecated on willful misinformation and blatent lies.
What we need is more efficient use of resources. We have ample non-arable crop land that can support livestock grazing. We need to stop promoting the growth of cotton and high water consumption crops in regions prone to droughts.
Most of these arguments that "we can feed the world" ignore that most people in third world countries are living in areas where food is not naturally abundant due to limited water supplies contributing to poor soil conditions and low nutrients, etc. that have afflicted the areas for thousands of years.
We can't feed people where food doesn't grow. Most farmers in those areas don't plant monoculture crops, they mix crops and produce more food per acre and per amount of water than we do in the west where water is abundant.
Frequently the first world does to the third world what England did to Ireland during the potato famine. These countries would be far less afflicted by droughts if we weren't encouraging them to grow cash crops for our use.