I think the study makes a giant presumptive leap to assume inbreeding was the cause of the higher-than-modern-human incidences of spinal tumors. It's irresponsible to assert this to be true instead of one of several possible explanations.
Another predator that went through a genetic choke point. Cheetahs did, too.[1]
Cheetahs survived, but they are so similar genetically that they get the same illnesses, and skin grafts between unrelated cheetahs are not rejected.
I think the study makes a giant presumptive leap to assume inbreeding was the cause of the higher-than-modern-human incidences of spinal tumors. It's irresponsible to assert this to be true instead of one of several possible explanations.
The study and the summary do not "assume" that the cause was inbreeding. They both assert that inbreeding could be a cause.
The article says "The team suspects these deformities and tumors indicate a lengthy history of inbreeding".
The paper abstract says "possibly because of an accumulation of expressed deleterious alleles that caused disturbances in developmental processes".
It's perfectly ok for scientists to write down and publish their speculation, as long as it's suffiently clear. I think it's quite clear in this case.
An assertion without conclusive evidence is an assumption.
Seems like there's also a sampling bias, where the less able-bodied animals are more likely to get trapped in tar for scientists to study.
Another predator that went through a genetic choke point. Cheetahs did, too.[1] Cheetahs survived, but they are so similar genetically that they get the same illnesses, and skin grafts between unrelated cheetahs are not rejected.
[1] https://academic.oup.com/jhered/article/108/6/671/3836924