Yeah, his theories about Neanderthals raping and eating humans for 50'000 years are a bit far fetched and better have a lot of data to back them up... I am actually thinking about hunting down that book of his.
But the idea that modern humans evolved from thousands of years of warfare against nocturnal rape-creatures that were six times stronger than us, a warfare that ended with the genocide of the losers, is certainly a good starting point for the average fantasy novel.