I thought you might try that argument, so I'm going to quote them again and now add in an additional quote.
"Their courage and
endurance are also
easily a match for any of the larger folk."
"D
warves are solid and enduring like the mountains they love,
weathering the passage of centuries with stoic endurance and little change."
"The dwarf god Moradin forged the first dwarves in his great workshop,
causing them to spring to life from inert metal when he cooled the heated castings with his breath."
"Moradin crafted the dwarves'
sturdy bodies, giving them the strength to
work for long periods of time."
"His
gifts of durability and purpose gave the dwarves all they needed..."
Additional quote...
"CONSTITUTION
Constitution measures
health, stamina, and vital force."
I notice that you avoided saying endurance when you point out what those quotes say. Stamina and endurance are synonyms. Weathering the passage of centuries with little change and durability equate to health.