Sure, and if you look at unit of bioavailable protein, ruminants win.
No, they don't. According to this paper:
- Eggs - 113% DIAAS
- Beef - 111% DIAAS
- Soy - 90% DIAAS
- Pea - 82% DIAAS
At the same time, the CO2 equivalent per 1kg of product (source):
- Beef (beef herd) - 99 kg
- Beef (dairy herd) - 33 kg
- Eggs - 4,7 kg
- Tofu (processed soy) - 3,2 kg
- Pea - 0,98 kg
Chicken eggs are slightly more bioavailable than beef, while being responsible for 7-21 times less emissions. Peas can be a hundred times less polluting, while being a relatively good protein source.
Except in high water environments (swamps and bogs).
Which agricultural lands typically are not.
You need to also account for wild ruminants
Total population of wild ruminants sits at around 75 million. The farm count is 3,6 billion, which is 48 times that. Wild rumimants, thereby, constitute around 2% of total ruminant population, the other 98% are domesticated. (source)
You also need to account for the bioavailability disparity between a whole food plant based diet and a whole food animal based diet. 3kg vs 0,5 kg in daily food.
Maintaining a vegan diet is more complex than simply removing meat and leaving the rest the same. One of the several points healthy vegan diets focus on is, exactly, gaining enough protein. For that, there are various protein-rich plants and processed products, protein isolates, yeast products. Moreover, vegan diet typically requires adding vitamin B12, as it is the most limiting factor of plant-based diets. Luckily, industrial bacteria can produce it very efficiently.
That said, eliminating animal food is not necessary. Poultry, pork, eggs, fish are all much better ecologically than beef. Beef is exceptionally bad from an ecological standpoint, and there are other, much better sources of same nutrients.
Type II diabetics
Vegan diet is not a contraindication for people with Type II diabetes, although basic meal planning, as always, is advised. In fact, vegan diet can improve cardiovascular health of such patients (source)
Going forward, I would like to ask you to provide academic/authoritative sources instead of linking to advocacy groups, which are highly biased.