The arguments against the meat & dairy industry are well known: chronic disease, depletion and pollution of natural resources, global warming, and above all the moral argument: enslaving sentient beings is wrong.
200 years ago in the US they were breeding human slaves [1]. Today they still breed chicken slaves and cow slaves and pig slaves, selecting for higher fertility and higher production of eggs, milk and meat. Then these animals spend all their lives enslaved, from birth to death, a life of absolute misery.
I'm not saying killing animals for food is inherently a wrong act, but enslaving them sure is.
[1] https://en.wikipedia.org/wiki/Slave_breeding_in_the_United_S...