From Infidel753:
I assume many readers have read or heard of Ursula Le Guin’s short story “The Ones Who Walk Away from Omelas” (summary and discussion here, full text here). The story describes a utopian city whose continuing good fortune somehow depends on keeping a single child in perpetual misery. Most of the inhabitants accept the situation rather than give up the happiness and prosperity this bizarre bargain affords them; others, unable to stomach it but apparently powerless to change it, simply leave Omelas — walk away.
Most present-day humans live in Omelas. Most present-day humans eat animal flesh in various forms, a practice important enough to them that they would not consider giving it up, even though they are at least vaguely aware that the industry which supplies this food inflicts enormous suffering on countless millions of self-aware creatures.
I started “walking away” almost a decade ago, starting with renouncing pig flesh after learning that pigs are much more intelligent (and in that sense more similar to humans and more capable of suffering) than the other animals we commonly use for food in the West. Eventually I gave up eating meat entirely, motivated less by abstract moral arguments than by simple abhorrence. Knowing that the differences between humans and other self-aware animals are quantitative rather than qualitative, I knew that their suffering also is fundamentally similar in kind to our own.