Why do people pretend that Neanderthals are not human?
It's a British problem -- Darwin said it, they believe it, that settles it. Chimp? Closest relative of us gracile moderns. Geographic origin of gracile moderns? Africa. Ironically, Virchow, who was not British and was opposed to Darwinism, spent the later years of his life attacking the Neandertal finds. His attacks devolved into the final gloriously stupid claim that the Neanderal fossil skeletal remains were those of an 18th century Cossack fugitive, who had rickets, and died naked, cowering in that cave.
Part of it has to do with evolution. Making the Neanderthals humans does away with a lot of link evidence. That is the sane and rational supposition.
Crackpot conspiracy theory follows but stay with me.
Let's say we manage to clone a Neanderthal. If they are not human why then they are animals and thus property.
There are a bunch of people in the world who do not like the fact that in advanced countries slavery is done away with. And it is not just the guys on top either. There are some bottom dwellers who wish there were still slaves around just because then they would have someone to feel superior to.
There is a movement on to make "not quite humans" who can be harvested and used like property.
People have some dark stuff in their souls.