This kind of thinking requires one not just to doubt the mainstream media, but also the way peer-reviewed science is conducted...
I do believe both mainstream media and peer-reviewed science are subject to the same pitfall of being conducted by human beings. There's also the fact that we do not live in an ideal world. I believe you mentioned this in a sense already, but to me it still somehow felt more idealistic than realistic. Short read on the matter:
https://www.economist.com/news/brie...elf-correcting-alarming-degree-it-not-trouble "
Scientists like to think of science as self-correcting. To an alarming degree, it is not"
I do believe it to be wise for one to be critical of their critical thinking too, which is much more easier said than done. In the grand scheme of things, there's just way too much information around for the bullshit to be properly filtered. It becomes a necessity to prioritize and suddenly we are missing things of paramount importance and taking things for granted that in hindsight we shouldn't have. Then there's lack of time and resources. There are plenty of wars being fought in the (mass) media, be they of ideological, economical, political or even scientific nature. History should remind us that science too can be and has been used as a tool of coercion and oppression.
Whether mainstream media is or isn't being used to influence/control human thought process and therefore behavior doesn't change the fact that it is in the mutual interest of both governments and corporations to do so. They've attempted it using LSD decades ago or or at least experimented on a governmental level, so obviously it is something of interest. The question of the topic was centered around media though, so let's consider the amount of money being poured into advertisement and the research surrounding it and its effectiveness. If we can be influenced in our choices of products by mass media, who is to say we can't be influenced in other choices and opinions too? I wouldn't even call it a conspiracy that there are extremely intelligent minds employed at for example google trying to figure out how to influence us in a manner that has the most impact. We have all these technological innovations like search engines, smart phones and social media gathering all kinds of data about us (with which we usually consent when we use said innovations) that we as humans couldn't even tell a fraction of it if someone asked us to tell them everything about us and our behavior that we were aware of.
So my question is, assuming there is at least some unconscious aspect to our behavior that we aren't aware of but some entity out there was, how could we even tell whether we were being manipulated or not? Would it be in the best interests of this entity to tell us? We can be talking about financial, political, ideological or any kind of interest in general, personally I believe it depends entirely on whether the entity in question profits from the release of this information more than it would from withholding it. For example if a competing entity had a much better capability to use the same information for their own gain and the intention was to undermine the efforts of said entity. Propaganda, counter-propaganda, counter-counter-propaganda and so on until we have definitely reached the point of information overload and we begin more susceptible to just choosing what is the most convenient for us as long as we can justify it and these days there's so much information around that you can justify pretty much anything if you want to. If you have monetary resources that are in the scope of billions for example, you can provide justification in the form of scientific 'proof' that smoking cigarettes isn't unhealthy for example. If your word has enough authority you can provide justification in the form of 'scientific proof' that witches should be burned at the stake for their own sake.
The recurring theme seems to be, at least to me, that we rarely see what's really going on right now or just fail to act accordingly. Only in hindsight and often too late do we realize that somebody played us when we are talking about the really fundamental stuff where the use of the terms like 'media controlled reality' is justified I believe, though of course to have a proper discussion we would need a better definition of the term than a comparison to the truman show. Most of the time it's just really subtle stuff we perceive as relatively harmless like product advertisement for useless gizmo of the year yet at the same time the same platform (mass media) can be successfully employed to influence our thinking regarding what's happening in, say, Ukraine. We may be getting constantly wiser in the sense the the same tricks don't work on us forever, but I'd hazard a guess that the ones adept at playing the game are usually few steps ahead of us.
Luckily we also live in a world where shady things come to daylight from time to time too, like the global scale surveillance conducted by the intelligence agencies. I'm pretty sure that one was an absolutely preposterous idea for most. Not much changed despite it becoming public knowledge though I suppose, so I'm pretty sure every media outlet in existence could make a collective announcement along the lines of 'yes, we are trying to influence the very reality as you perceive it using modern techniques and technology on a daily basis!' and people would continue to live their lives largely the same. Besides, it's not always a bad or sinister thing either, certainly not a black and white thing. Sometimes the reality is both unavoidable and devastating and unless the way we perceive it is influenced, people might lose hope. Some disease or mental illness for example, the reality is that there is just so much we don't know that if general people really grasped that idea, we might have a lot more suffering around due to there now being no more working placebo treatments. If scientist and medical professionals didn't believe with confidence that the underlying fundamentals are solid, how would they convince anyone either?
The most important thing is the freedom to perceive reality however you want. To have that we need to respect the same freedom for others too. As long as we aren't enforcing the way we perceive the world on others or discriminating using the worldviews of others as our basis, we should have the the freedom of expressing ourselves too assuming it isn't violating human rights in general. To put it simply, nothing wrong with trying to influence or control the behavior of people through words, as long as you aren't trying to incite violent behavior (or inaction when the one trying to influence is the violent party) for example.
Speaking of which...
http://www.wired.co.uk/article/open-letter-to-google-axel-springer
And here's a good one from "Ex-Google Design Ethicist" (is there actually a degree in product design ethics these days?)
https://journal.thriveglobal.com/ho...ian-and-google-s-design-ethicist-56d62ef5edf3