I strongly disagree that the news media is a reliable source of unbiased information. It is true that news media is very helpful to large number of population who don't have ability to investigate every current issues and political events, however, it cannot be unbiased at all. It is impossible that news media to be entirely rightful source of information for following reasons.
First off, every human being including journalists cannot be entirely objective. Each pesons has their own view of perceiving/understanding incidents or phenomenon. Only mechanic apparatus would perceive world with no opinion. Even if a good journalist and editor try to be neutral on making news, they already have their own notion of 'neutral', so it is not possible to produce perfectly unbiased information on what happened.
Next, there are historical evidence that shows news media has been often involved in distorting facts and intentionally misinterpreted truth. For instnace, when Korea were under military force government, most medias reported only government friendly news, moreover, few journalists who protested were arrested and disobedient news companies were forced to close their printing factory. This shows how news media is easily subject to power.
In conclusion, expecting news media to be unbiased is difficult.