Sin has no point whatsoever, being that I already said that a strongman wouldn't be immune to being hit by a car that he could pull, all his cute quip showed us was that the moron has reading comprehension failures.
To perform any strength feat, as a prerequisite your bones, muscles skin tissues, etc whatever, have to be able to withstand at least the force necessary to output the strength feat.
Animals for example bite with a certain force but their skulls are made to withstand more force than they can output. This is just a basic biomechanical safety issue.