Bernardo I do agree that most or none of us have read the book and are basing opinions on the facts presented in the ‘blog’ article. Certainly we might view the idea that the 50 individuals referred to as the remaining ‘human’ population individuals may refer to the number of untainted at that time while the rest of the ‘blended’ population from which breeding continued was the stable number.
.......genetic evidence to show that this prolonged period of cannibalistic and sexual predation began about 100,000 years ago and that by 50,000 years ago, the human population in the Levant was reduced to as few as 50 individuals.
What I do find difficult is that if the depicted artist renderings (attached here) are correct, then even with breed-blending, a span of even 100,000 to 50,000 years does not seem long enough to have modified to present day human physiology. While predatory eyes often have the vertical pupil for example (and not predators have this), I find it also unlikely that attribute would have become so modified in that short length of time either. I’m not a scientist though so I cannot really make such an educated guess anyway.
Note: these images do remind me of bigfoot though so perhaps there are surviving unblended neanderthals