I am sure that we both agree, Chuck, on the silliness of that reason - I guess that some-one bent a Decathlon in the early days by bouncing and bouncing and bouncing .... and the boss said don't do wheelers so it has remained as tribal knowledge ever since.
The abysmal stupidity of some of these decisions truly stretches the outer reaches of understanding.
Using that thought process why not just ban all flying.
The Decathlon is one of the most benign tail wheel airplanes ever certified for flight, if a training pilot can't wheel land one maybe they should get further flight training and once they can fly the Decathlon maybe try teaching again.