Progress ?

I found this picture on the blog of Yellowdog Granny, and I have to admit it is rather thought-provoking -- and troubling. Mankind likes to think it is better than the other animals, more evolved. Are we? Isn't there something at least a little bit wrong about caging our cousins, and then enjoying a field trip to see them in that cage? Could this be why so many people want to deny evolution -- because if it is true (and I believe it is), then how can we justify the way we treat other animals (animals that once had a common ancestor with us)?
I'm not a vegan or vegetarian, and I don't like the tactics of groups like PETA. But I do think humans have an obligation to treat others animals kindly, and to avoid any kind of cruelty -- and caging other animals for our own amusement strikes me as a kind of gratuitous cruelty.