I guess one way of looking at it is if you starter can still crank with killswitch engaged, there is chance of burning something out overcranking it.
That is user error. I gave a person with a Dodge Avenger a jump but something else was wrong. It cranked but never tried to start. I told the person several times -
STOP.
a week later....
My neighbor was cranking and cranking and cranking an old diesel dump truck that he let sit for 2 years without starting. It runs 2 huge 12v batteries in series to make 24v.
STOP you'll burn up the starter. Fix the issue, let the starter cool down, shoot some starting fluid and try again. He did a few hours later and it started in a giant nasty
TOXIC cloud of blue and black smoke.
Starters draw a LOT of power! Remember - in the case of a motorcycle or manual transmission car / truck - it easily has enough power to move the entire vehicle - if started in gear!