This discovery is a fascinating and, to some, surprising revelation about human history and evolution. But that is all it is. Humans have evolved beyond a lot of primal needs, such as body parts like the appendix, certain muscles, and even tails.
We no longer need to hunt and gather, be greedy with our food and territories, or seek out simple shelters like caves in order to survive.
Cannibalism is another one of these traits which once served humankind's need for survival, but is no longer necessary and is even in some cases detrimental to our health.
Cannibalism was an adaptive behavior that humans once needed in order to survive, and later fell back on when they were desperate for food or cures for ailments. But as we have evolved, so have our needs evolved, and we no longer need to resort to cannibalism to full our bellies. We are more educated about how it does NOT, in fact, cure our ailments. And, as a result, it is no longer an ethical practice, but an unethical one for reasons of morality and of human safety (both for the eater and for the consumed).