Not the original commenter, but wanted to add some rebuttal to a few of those claims

In terms of health

It is the position of the Academy of Nutrition and Dietetics that appropriately planned vegetarian, including vegan, diets are healthful, nutritionally adequate, and may provide health benefits for the prevention and treatment of certain diseases. These diets are appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, childhood, adolescence, older adulthood, and for athletes. Plant-based diets are more environmentally sustainable than diets rich in animal products because they use fewer natural resources and are associated with much less environmental damage. Vegetarians and vegans are at reduced risk of certain health conditions, including ischemic heart disease, type 2 diabetes, hypertension, certain types of cancer, and obesity. Low intake of saturated fat and high intakes of vegetables, fruits, whole grains, legumes, soy products, nuts, and seeds (all rich in fiber and phytochemicals) are characteristics of vegetarian and vegan diets that produce lower total and low-density lipoprotein cholesterol levels and better serum glucose control. These factors contribute to reduction of chronic disease

https://pubmed.ncbi.nlm.nih.gov/27886704/

In terms of costs

It found that in high-income countries:

• Vegan diets were the most affordable and reduced food costs by up to one third.

• Vegetarian diets were a close second.

• Flexitarian diets with low amounts of meat and dairy reduced costs by 14%.

• By contrast, pescatarian diets increased costs by up to 2%.

https://www.ox.ac.uk/news/2021-11-11-sustainable-eating-cheaper-and-healthier-oxford-study

In terms of issues with crop production

Those end up being reduced due to the lesser need to grow crops. Is it perfect, no, but does it end up substantially ahead, yes

So for instance terms of pesticides, the usage still ends up lower due to a lesser need to grow feed crops

To produce 1 kg of protein from kidney beans required approximately eighteen times less land, ten times less water, nine times less fuel, twelve times less fertilizer and ten times less pesticide in comparison to producing 1 kg of protein from beef

(emphasis mine)

https://pubmed.ncbi.nlm.nih.gov/25374332/

More broadly

Plant-based foods have a significantly smaller footprint on the environment than animal-based foods. Even the least sustainable vegetables and cereals cause less environmental harm than the lowest impact meat and dairy products [9].

https://www.mdpi.com/2072-6643/14/8/1614/htm

This is because

1 kg of meat requires 2.8 kg of human-edible feed for ruminants and 3.2 for monogastrics

https://www.sciencedirect.com/science/article/abs/pii/S2211912416300013