high school kick off into end zone rule

[number 26]

hello
does anyone know why, in high school, if the kick off is into the end zone, it's not permitted to be run out?
automatically placed on the 20 yd line.
one would think, maybe, it is to protect players from long run back type injuries.
but, that doesn't quite make sense.
nor, could i come up with any explanation.
perhaps it's a rule in need of revision.
thanks