Humans generally eat only vegetarians and some omnivores, but not carnivores. People don't eat dogs, not only because of their feelings relating to pet status, but because carnivores contains pathogens, taste awful, and wild carnivores are pungent. Few hunters or trappers eat coyote or wolf -- even if they skin them for their coats and to control their population -- because they smell pretty awful and have a nasty taste. Most omnivores that humans eat, such as chickens and pigs, primarily are fed a vegetarian diet (e.g. grain), and only consume animal flesh such as a bugs and mites incidentally.

Horse meat is kind of a strange one though -- horses are vegetarians but most Americans don't eat horse meat. Some cultures eat horse meat, and there is no biological reason for not eat horse meat -- unlike eating dogs, coyotoes, or other carnivores.