I've searched and searched and been unable to find any evidence of any harm caused by TV radiation, or even harmful levels.

You're right the first testing took place in 1968 after the National Center for Radiological Health was formed, but it only found that a few larger TVs emitted a "thin crescent" of radiation pointed downward, and did not pose any threat to viewers. The head of the National Council for Radiation Protection at the time, W. Roger Ney, said that the amount of radiation was “too little to have a measurable effect on human beings.”

Again, you could measure the radiation, but it was insufficient to have an effect on humans.

You've gotta remember this was the 60s and people were terrified of radiation. The "dangers" were wildly exaggerated by luddites, and you're perpetuating it even today.