TV is one of worst forms of media out there. It is practically the definition of mind control and although there are multiple channels, there is a strange sense of groupthink.
This is similar to the Murray Gell-Mann amnesia effect, where famed quark discoverer Murray Gell-Mann opens the newspaper and reads a physics article. He is disgusted at the lack of research, the blatant misinformation, and random theories disguised as respectable reporting. Then he flips to another section - like politics or war - and reads it as if it was somehow more accurate than the nonsense he just read.
Social news online is even worse. At least with TV, there's a chance you'll be shown something from outside of your bubble. Polarization increased with deregulation of TV political coverage in the US. The internet has never been regulated in such a way, and has given rise to hyper-polarization.
Although the internet allows for hyper-polarization, it also makes it easier to manage group polarisation by allowing alternative views to be only 1 click away. It's just intellectually easier to select information from places that confirm your biases and polarize them rather than be challenged and consider alternatives.
This is similar to the Murray Gell-Mann amnesia effect, where famed quark discoverer Murray Gell-Mann opens the newspaper and reads a physics article. He is disgusted at the lack of research, the blatant misinformation, and random theories disguised as respectable reporting. Then he flips to another section - like politics or war - and reads it as if it was somehow more accurate than the nonsense he just read.