Thanks cognisonance ,I read your article and it makes many valid points which I will try to address to the best of my ability .While I'm answering it I'll try to brake it down to small sections so we deal with one thing at a time.
1. Anthropomorphizing animals :Much of the question of cruelty involves the tendency of humans to anthropomorphize animals. From early childhood, we are shown animals acting like humans. In cartoons and comic strips, animals talk, kiss, read, dance, play golf, and sing as humans do. Films like Lion King have carried the tradition of Disney on with the same effect.
The inability to distinguish between fantasy and the real world has become a problem in many ways in our culture, but it is especially serious when it results in human suffering and need. Animals are not humans and the portrayals that give them the total range of human abilities and feelings is at least misguided.
As I said earlier the more complex the biological entity the more complex it's nervous system and therefore it's ability to feel pain .
2.Animals do not feel pain as we do. Pain is a psychological experience separate from behavioral reactions to injurious stimuli. Pain involves both perception and an emotional response. When you hit your thumb with a hammer, there is an immediate perception that you have been injured. The emotional aspect that follows involves suffering, but is not necessarily a part of the perception. You can have a great deal of pain that results from the death of someone you love and not have any perceptual response at all.
The term nociception refers to the detection of an injury by the nervous system (which may or may not lead to pain). A starfish has a primitive nervous system that interconnects sensory receptors that detect injurious stimuli with muscle cells that cause movements enabling the starfish to move away from nociceptive stimuli. Starfish have no brain so there is no pain.
The human central nervous system has a large cerebral hemisphere and a brain stem connected to a spinal cord. Nociceptive stimuli can cause an immediate protective reaction called a reflex, but pain has not been felt by the person. The nociceptive activity is transmitted to the brain stem where additional protective reactions take place (avoidance responses, verbalizations). The nociceptive activity is transmitted from the brain stem to various parts of the cerebral hemispheres where it activates conscious awareness of the nociceptive stimulus and generates the emotional unpleasantness of pain.
In a fish, you have a simpler version of the spinal cord and brain stem, but the neural functions are similar to that of humans. The cerebral hemispheres of the fish lack the regions necessary for conscious awareness and for generation of pain experience. Awareness of pain is associated with the brain stem and spinally generated behavioral reactions.
All mammals have enlarged cerebral hemispheres that are mainly an outer layer of neocortex. In humans, this neocortex is massively developed and this is the key to our ability to experience pain. If the cerebral hemispheres of a human are destroyed, a comatose vegetative state results. If the cerebral hemispheres of a fish are destroyed, the fish's behavior is normal in most ways. The unpleasant part of pain in humans is generated by specific regions of the frontal lobes of the cerebral hemispheres. Other mammals have radically different sized frontal lobes. The brains of sheep and deer, for example, have a tiny fraction of the frontal lobe mass that humans have. Their perception of pain cannot possibly be anything like ours. Note: The above data is from an article by Dr. James D. Rose, Department of Zoology and Physiology at the University of Wyoming, Laramie, titled "Do Fish Feel Pain?," In Fisherman, December, 1999.
