They say they’re taking about tensile strength at the footnote. But teeth would be more likely to be compressively strong. They don’t get pulled on much.

The whole thing seems very confused. Anyway let’s build space elevator?

Given what they are talking about (mollusk tongue scraping rock) tensile strength is appropriate. The mollusk does f crush food between teeth - its teeth are on its tongue and scraped across rock.

Yeah, they're conflating strength, hardness and toughness all over the place.