The very concept of "truthful" Mass media/Journalism is self-defeating. If mass media stops feeding propaganda and instead starts telling the truth, then the majority of the people will need to have their very own opinions, which will destroy the very concept of "majority" and "masses". As we all know, the masses can't have their opinions form without state/journalist propaganda. They simply don't have enough brains/time to discuss the complexities of our world, so they just turn on TV/read a newspaper/go on The Internet, and trust all the biased bullshit the mass media/journalist spews. For example, if in my country (Russia) the mass media suddenly starts to tell the truth about the pro-Russian terrorists in the Ukraine, and how they hurt, rape and mutilate their own former friends and acquaintances just because they heard that Russia has better paychecks (not really) and that Ukrainians just want to take their rightful territory from the terrorists back, then it will give your typical Russian citizen an existential crisis (if he's not too blinded by nationalism, of course). So yea, if the very essence of mass media is to being biased, then how it can be "truthful"? Hell, the majority of Russian citizens will claim that Western mass media cannot be trusted because they are (OHMYGODOHMYGOD!!11) biased against the Russia. Same will say the majority of Westerners about Pro-Russian mass media, "they cannot be trusted because they are biased against the West". We all love One True Bias/Source™ while dismissing the other biases/sources as "wrong ones".
TL:DR - There cannot be a "truthful" and "unbiased" mass media/source because the very essence of the mass media (and humans as a species) is in being biased. Of course, it's my opinion, you don't have to agree with it. After all, it's "Unpopular/Controversial Ideas Thread"!
@ itisnotlogical - ChairmanPoo's avatar makes me a little bit uncomfortable. I think I'll just AdBlock the avatar to don't see a muscular body with a face for a crotch.