The actual reason TV is banned in Waldorf Schools is an occult one.

"We must also be active in the consciousness soul when we struggle to balance the forces of evil, Lucifer and Ahriman , who are always present in the picture of the human being.

...Before the time of radar, television , and computers, Rudolf Steiner prophesied that these elemental beings would enter our time with an abundance of inventions. He told of the three forces of magnetism, electricity, and nuclear energy that these beings used. This does not mean that these inventions should be avoided -- they belong to the age of the consciousness soul -- but it is most important that enough weight be put on the other side of the scales. ... These inventions, which increasingly fill our world, need to be balanced by the faculty of imagination. This is the secret to how we can deal with the forces of evil."

Helmut von Kugelgen, Director
International Waldorf Kindergarten Association