Indeed. I assume a major factor is that the larger the animal, the harder the slaughter is to deal with. That's why we say "beef" and "pork" instead of "cow" and "pig"—it creates distance. For years they thought fish didn't have feelings... they were wrong. People do use demeaning terms like calling someone a chicken, or a dirty rat, or a fat pig, or a cow, or say that something smells fishy... All these things are mental gymnastics that create an us versus them. Meanwhile domesticated animals like dogs get phrases like "puppy eyes" and "man's best friend"—we elevate what we don't eat and degrade what we do.