It is observation, that the media seems to greatly influence public perception of reality
Personally, I would say something more like "the media seems to cater greatly towards the paying public's desired and/or feared perceptions of reality."
does the media reflect things just the way they are?
IMO it's a feedback loop in a reciprocating cycle.
are they forced (for the sponsors to pay the bills) to reflect things the way their audience seems to want to see them?
IMO it's important to consider there are actual people running the "media."
They've consumed their own product too.
They are trained and socialized by the same people consuming their product.
They don't grow up in a vacuum and all of a sudden, completely objective and unaware, wonder "what am I supposed to do? What am I supposed to say? I know! Let's manipulate people this way."
The same biases pushing people to consume media are pushing the people that produce it.
Other than that, thank Ted Turner for the 24/7 news channel and the need for constant content that keeps people watching, then thank your employer for giving you enough disposable income so you can afford cable and have enough time off to watch it, then thank yourself for wanting constant "news" consumption.
they showed enough to shape what the viewer THOUGHT they saw
They didn't shape the bias of the viewer.
That already existed.
Show that blocked dancing twinkie thing to a 6 year old without a concept of masturbation and you'll get a different response than from a 30 year old single guy.
Most media doesn't create bias, it simply takes advantage of, or exploits, one that exists.
Some does so intentionally, some unintentionally, some with a specific agenda, some with a non specific agenda.