Heinrich Hertz was unable to deflect cathode rays using an electric field suggesting that they did not have charge. Hertz also discovered that cathode rays could pass through thin gold foil without damaging it, meaning that they had no mass, leading him to believe that it was a possible form of electromagnetic radiation. Furthermore, there were objections to the paddle wheel experiment because it was though that the cathode rays heated one side of the paddle, causing the gas in contact with it to heat up and expand, thus causing the paddle to move. This soon became known as the radiometric effect as discovered by J.J Thomson in 1903.So my question is, why was there any debate as the observations from the paddle wheel experiment seem highly conclusive.
^ The answer to your question (Assuming it wasn't a rhetoric question )
This information surprisingly came from In2Physics