Because he was a desperate idiot who not only stole and copied a lot of other peoples' work prior, he also couldn't face the facts that the silly theory of evolution couldn't bridge the missing link (among many others) between the ape-like Homo erectus and the modern humans of today (Homo sapiens). The whole theory is a fallacy and its current intent is to distract people from real science, biology and actuality. I'm amazed at the number of people, with or without poor cognitive function, that still believe in this crazy religion of evolution. In better words, it is one big load of steaming dung! I almost feel sorry for the people that are really that gullible; it's asinine! Single-cell amoebas really do all that, eh? LOL!