Roger, all of this assumes that humans beings, in our intelligence and sense of morality are more important than other animals. That assumption is how we are able to treat animals so poorly. That assumption, in relation to humanity, allows us to treat other social groups or individuals as “lesser”. Throughout history, this has been the case - different groups being singled out as less intelligent or less moral, in order to justify some abuse or another (slavery, pogroms, ethnic cleansing, etc.).
To most of us here, that assumption of inflated importance is false. Plenty of reasons have been given in this thread as to why it is false. Saying “men are just animals” in that context is merely a denial of the above assumption, not a denial of the things that make humans different from other animals.
In other words, our current treatment of animals and the abuses we have inflicted on each other over history, even in the present, are consequences of a false assumption.