You've pretty much wrapped it up. It is very true just how shockingly powerful the media is and most people greatly underestimate it thinking they're different, although a certain awareness of this allows us to put up some resistance. If you control the media, you control most of the people. Anyone who wants to take control of a country fully understands how powerful and indoctrinating the media is when TV and radio stations become high profile targets. People's entire views of the world and many people who they've never even met, but seem to think they know well including leaders who know full well how to act when in front of a camera are based entirely on what the media tells them to believe and people are massively influenced all the time, often without realising it or certainly understanding the full extent of it, but it's even more powerful as people grow up. You are also right about the news, they could be described as merchants of chaos because there's nothing like bad news to get the money coming in. I covered the drugs side in my reply earlier, although a lot of people don't understand the extent of this either including how corrupt and powerful the pharmaceutical companies are, so I also agree. And yes, finally environment factors and stresses triggers it.
I don't believe everyone who lived exactly his life would have ended up killing people, but I do believe we are all capable of killing under certain conditions and even though some people are easier to condition than others, I also think it's possible to condition anyone to kill, especially if the conditioning/indoctrination starts from when they're very young. If people don't believe me, then here is an example, if the media suddenly states that your country is under threat from a hostile and evil force, then if they bring back in national service, the army will condition most people to kill and the people fighting will fully back their country, truly believing they're right. Similarly most of the German soldiers who fought for Hitler believed they're were doing the right thing when they were also conditioned to kill on the battlefield.