Bloomberg too runs with the sensationalism:

Ancient Toe Bone Shows Incest Role in Neanderthal Decline

The findings suggest the population of Neanderthals was small, making inbreeding more common among them than among ancestors of modern humans, said David Reich, a study author and professor of genetics at Harvard Medical School in Boston. The low levels of genetic diversity also may have made them less fit over the long run, leading to their extinction, although that is still conjecture, Reich said.