A person that does not realize that there are more small animals brutally killed per year by the machinery used to harvest grain than all of the cows and pigs that are slaughtered for our consumption.
A person that choses to eat vegetables because they're easier to catch.
A person that does not realize that plants are arguably just as alive as animals. They grow, they reproduce, and they respond to external stimuli, just like an animal. As a result, vegans promote the "ethical" slaughtering of millions of plants.
I'm a vegan and I don't want to think about all of the animals that are being killed for me to eat and have clothes. I also don't consider the rights of things that aren't cute and cuddly, like plants.