TV like any other thing in the world can be used for good, bad, and unknown. Fire can cook your food, or burn down a forest. Nuclear material can be used as energy, or it can be used as a bomb.
The point is that TV in the abstract is neither good nor bad. But, in specifics it can be good or bad.
We can learn a lot watching TV and we can be subliminally guided by TV. It of course depends on the person watching the TV. They select what they watch, and unfortunately many TV watchers just follow the trend. This is emulated into voting habits, which is just another avenue from the same personal selections.
There are 1000s of TV stations, and magnitudes more of TV shows. Unfortunately, imo, there are much more shows that fish for the idiots, than the brilliant. I don't know about the audiences for these shows, so I can only assess the values from the shows themselves. If this was a slab of beef, it has more fat and grizzle than beef.