I don't think he needs any proof to back his claims as by just observing you can easily notice this. The Media has  more bigger audience and rhe general public tends to rely on them for their everyday information. If they decide to hype a certain propaganda it affects the market either negatively or positively. Trump's hate speech on bitcoin had no immediate impact until the media decided to hype it by constantly repeating it and other media source followed making the speech a norm in the space and it affected the market negatively.

In the real world we know, this media platforms are responding for some unnecessary attention given to things such attention shouldn't be given to. They hype certain news that profit then while down playing others. Information is power which means anyone who has control over the information control the power.