Generally things are engineered with a safety margin so that they are absolutely safe for regular use and minor manufacturing defects or unusual usage don’t cause immediate failure. That ladder rated for 400lbs will hold more than 400lbs before it collapses. Sometimes much more. This is normal and sometimes manufacturers like to show off how far above spec they are.
That said, the human jaw is quite strong, and structural wood is not generally expected to withstand high perpendicular shearing forces. I also don’t really believe Tesla solar roofs would hold up to bowling balls, despite that being essentially a very extreme piece of hail.