[serf]

>I mean, wouldn't sensitivity be the default assumption? Why were they otherwise convinced?

I don't know if it's a related assumption, but it was at one time thought that the t-rex had sacrificial/re-growing teeth like a shark ( I don't follow this stuff much, so I don't know how dated that premise is. )

Maybe the assumption goes something like "Hyper-carnivores lose and re-grow their teeth routinely, so let's assume that their physiology has done something to negate the pain associated with the process."