As with any medium, you have to apply filters to experience quality. The basic experience of television goes totally against this, though. You turn it on and get a constant stream of whatever is on at the moment. If you don't like it, you can change streams. It's dazzling and more than a little hypnotic. The radio is like this too, but less engrossing since there's no visual stimulus.
I prefer on-demand media to this kind of streaming media. With a record or a film, you get to actually choose what to watch, and this makes all the difference. You can apply filters. If you're just sitting at home channel surfing, you're going to end up watching a lot of crap you wouldn't have bothered to deliberately leave your house for.
This isn't to say there's no good TV content, just that the traditional medium of TV is better suited to deliver metric tons of total crap. But this content still ends up on on-demand media, and frankly a lot of TV content is best watched this way anyway. If "no filtering" is the primary problem, this is the solution.