Boxing the wake cracks Pawnee tail tubings or long term fatigue?

Boxing the wake causing cracking of frame structure in a Pawnee is just nuts. The impact of the tailwheel on the pavement during landings has to be much more significant.
So...we are to illiminate a basic flight competency, boxing the wake, because the tow planes are so underengineered that they are getting ruined by the soft lateral loads imposed by boxing the wake?
Why not. Spins are obviously dangerous and very stressful on the airframe so we have to elliminate them.
Loops involve 3.5-4 Gs which is obviously a great stress on an airframe so those must be illegal.
My G meter has registered 5 Gs from flying through rough air so flying through rough air must be made illegal.
My G meter has registered 10 Gs from trailering so trailering a glider is obviously stressful to an airframe so that must be made illegal.
How do we survive?