I don't like eating animals that have been bred to be dependent on humans for survival. Especially when the entire point of their domestication was to live alongside us, unlike sheep/pigs who were domesticated to be eaten.
Dogs are bred to be obedient and retain a childlike (cub-like) mental state, so that they can be trained more easily. Seems particularly cruel to turn around and start eating them. Would sooner eat a wolf than a dog, even though they probably taste the same. Or I wouldn't really have a problem eating wild dogs.