Most countries subsidize agriculture to protect it from competition. In countries like the US the subsidies reach billions of dollars a year. The burden of subsidization falls on tax payers, and this money could be allocated in a way that prioritizes humans flourishing: education, medical care, humanitarian support of starving countries.
In food production, generally speaking animal rearing is the highest GHG producer, highest water spender, highest land user and deforester, and energy spender. If globally we eliminated animal foods, we would minimize land and water use by 75%, [...]
Food production is responsible for 25% of our GHG emissions, and reduction of 75% of those emissions would reduce our total emissions by 19%. 1 kg of beef produces 60 times more GHG than 1 kg of peas.
This is something that most humans care about. Our gluttony for animal use exploded the biomass of farmed animals while reducing the biomass of wild animals. From destroying their habitats to killing them because they intervene with food production. Examples: wolves who try to predate on livestock, badgers who are blamed for the spread of Bovine Tuberculosis in the UK, and even animal deaths for crop production that are intensified by the need to grow animal feed.
5. Mentally - when we don't like a group of people, we dehumanise them, which includes "downgrading" them to animal status, and treating them accordingly. Animal practices were used to holocaust jews, romanos, lgbtq in 1945, and today we also gas pigs to death.
6. Speaking of badgers - disease. Zoonotic diseases are the worst diseases that have been plaguing humanity, especially in the past 100 years - the flu, AIDS, COVID, TB, and about to get another avian flu. There are other ways, but I just woke up, might add to this list later.
7. Health - the leading causes of death are related to overconsumption of animal products. Processed meat type 1 carcinogen, sat fat & cholesterol are linked to heart disease, and it's easier to overconsume on an omni diet, which leads to obesity, increasing risk of diabetes etc
8. Leather destroys entire regions (look up Kampur leather).
9. Waste of resources - supplements and edible calories