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.

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.

Yep. For instance it could be from higher cosmic ray penetration into the earth during the last geomagnetic excursion.

Cats don't really chew much anyway. If sabre-tooths have a rough tongue like other cats, they can probably scour flesh off bones with that with little need to work over the meat with their teeth.

I know I'd certainly be discouraged from feeding if I got the sabre toots.

> These sabre toots seem to get in the way of feeding and chewing.

Why? They don't stop the mouth from closing. Presumably they don't stop it from opening either.

Compare walruses, elephants, and pigs.