By George, I think he's getting it.
There is a problem with this view. Can we say that "unfitness" is "unnatural?" Not really.
The persistence of unfitness certainly is unnatural. Unfitness has a tendency to be selected out of the gene pool in the most final way. That is essentially the definition of unfitness and fitness. Fitness persists, unfitness doesn't. A changing environment (which can include the living competition both in the same species and other species) alters what is fit.
"Unfitness has a tendency to be selected out of the gene pool in the most final way."
Except where the natural processes are being screwed around with. As an example, I give you modern humans through the use of modern medicine.