In the end, any competitive theory must do more than point out anomalies. It must explain and it must provide direction for research.
They explain, but they explain through a prism with no proof. The only evidence given was that gorillas and chimps had something that humans did not have. They then force fit the solution to achieve an end. As I understand their solution, Hugorimp had alleles, one with virus. Gorilla left hugorimp and fixed the allele with the virus in its genome. Huimp then spawned human and chimp, with humans losing the virus allele and chimp keeping the virus, but losing the one kept by human. Quite a just so story.