It's not anthropomorphizing, it's not putting humanity on a pedestal when it comes to programmed or instinctual behavior. We are animals. Our natural selective advantages are just in the areas of intelligence, language, and ability to use both to develop more advantages for greater adaptability to new environments or problems.
Science continues to discover that animals have more intelligence and complexity than we wanted to give them credit for, so honestly little surprises me in that department. The only reasons I can see for denying this would be religious teachings that say the Earth and everything on it are gifts from a supernatural being to be used at our whims or for those hostile to vegan/vegetarianism who don't want to have to empathize with their equivalent of a walking Big Mac. Then wanting to think animals are just pretty background waiting to be harvested for useful items makes sense, nobody wants to think of themselves as being "bad" so if they don't think or feel pain (or anything at all) then easy-peasy.