We are designed to function in a completely different way.
See now, this might be nothing more than human arrogance. There is absolutely nothing humans do that is unique to our species. The differences are of degrees, not in "how we are designed to function". We have a rather advanced ability to think systematically, but there are animals with the same skill. It's only less evolved.
Anyone who has ever had a pet knows that animals have emotions. Anyone who is inclined to disagree are either ignorant or arrogant.
The worst cruelty against animals comes from those people who see animals as something less than living. Those who think that they are not really sentient, so it doesn't matter if you pull the skin off and leave the animal to die slowly.
So it is cruelty out of ignorance. What scares me is the will to guard this ignorance, so that we can keep up the profit... Shameful, if you ask me.