Eating animals is an option, not a requirement, and it comes with serious ethical implications. 
Exploiting
 and killing animals for food is inherently violent and inconsistent 
with our natural empathic tendencies, so we have developed social and 
psychological mechanisms to maintain our meat-eating habit. We have 
become largely disconnected from the painful reality of exploitation and
 slaughter, keeping it out of sight and out of mind. In the rare 
instances when we are forced to confront our subjection of billions of 
animals each year to unnecessary suffering, we fall back on the human 
brain’s great capacity for rationalization. We have come up with good 
reasons to do bad things for thousands of years. The techniques we use 
to excuse the eating of meat are the same we have used to justify other 
violent institutions and prejudices throughout human history. 
Humans are social animals, and we learn behaviors, including how and 
whom we eat, from those around us. In carnistic societies, members 
unwittingly support businesses that engage in systemic cruelties and 
conspire to look the other way. But humans are also hardwired to feel 
empathy. The concept of carnism is a useful tool to understand and 
deconstruct a dominant institution that stifles our innate compassionate
 impulses.
From the blog post Why Carnism Matters by Gene Baur
