It's scientific inaccuracy is in its implicit assumption that humans started as creatures very similar to modern chimpanzees, and that is a fundamental misunderstanding of how evolution works. In fact, genetic analysis show that human and chimps (+bonobos) split from a MRCA most recent common ancestor) between six and seven million years ago, and that creature, chimp and human great great great ... ancestor possibly no more resembled modern chimps than it did modern humans (the most successful ape species on the planet today.
Actually, fully upright walking and possible hairlessness existed in our ancestors at least four million years ago, and maybe even more than five million. If our facts are right, we are getting very close to the human/chimp ancestor split; close enough, I am suggesting, that that ancestor itself stood upright and might have been hairless. Indeed, with the exception of intelligence and brain size, it might have been much closer, in physical form and some behaviors, to H sapiens than to P paniscus. Possibly it even had a larger brain and intelligence that modern chimpanzee.
This at first sounds absurd, I know. But that's due to the "evolution is progressive" bias we all tend to carry with us. Yet bias is all it is; nature does not have to function that way, or any other way we may preconceive. The "chimp line" from this H/P ancestor might have migrated into the jungle, where natural selection favored smaller, hairy bodies, with smaller brains, and limited upright motion (chimps normally "knuckle walk"), a locomotive means that help them on the ground and in the trees, where modern chimps live.
Based on human fossils, the human ancestor was probably a small animal, on the order of a modern chimp or less. For whatever reason, it migrated into the open savannah that was already developing in eastern Africa five-ten million years ago. There, its upright gait and possible hairlessness would have conveyed distinct advantages -- in walking, migrating, carrying food, weapons, and children, advantages that we enhanced in time by natural selection until we reach the human beings of today, the most successful apes in the entire history of the family.
Of course, if all this is true, we then ask ourselves where and when and how upright gait developed in the first place. Here, unfortunately, our fossils so far (and any DNA they contain) are frustratingly sparse. Modern consensus holds that apes first appeared in Asia, 20-30 million years ago. There then, is the place to hunt for solid facts.
