I'm having a similar reaction to the movie '30 Minutes or Less'. The premise is that this teenaged pizza delivery guy gets ambushed, crammed into an explosive vest and sent to rob a bank. If he succeeds, he gets the codes to get the vest off. Hilarity ensues.
In reality, the pizza guy was middle-aged, and it was a collar bomb. He was going to get clues and 'additional time' as he completed each part of his task. He got his head blown off on camera while the cops were waiting for the bomb squad. They later determined he wouldn't have possibly had enough time to complete the clue-hunt.
If I'm understanding you right, the real-life pizza runner bomb incident inspired the film, but the film changed his age and so on. This is where reality shines through to some viewers and that does create a "jammed perception" with some of us . I think this is the responsibilty of film makers, not of us as viewers. It must have been obvious to those who did the film that many people would recognize the original incident.
I remember a similar cross between the r/l crime and a film based on it. On a winter night in 1986, Olof Palme, prime minister of Sweden (and one of the most charismatic and polarizing political people in the modern history of the country) was shot down in the street in Stockholm. The assassination remains unsolved to this day and it's the only time in modern Scandinavian history that a PM has been killed, during their term or after. At the time it was as much of a shock as the recent Oslo/Utöya attacks, and it remains an open wound with many people twenty-five years later, not least because it was never cleared up.
For many years, film makers and fiction writers avoided directly picking up on the murder; there were barely even documentaries approaching it, though the news media were returning on the tracks in various ways of course. About ten years after, the first - and so far only - attempt to make a thriller based squarely on it arrived, a film called The Last Contract.
It wasn't a good one, it was a hotch-potch of nods to different strands and theories with the main track being a professional killer brought in by backers both Swedish and foreign to take out the PM, for vague political resons. It would have been okay to take the film as fiction if it had at least been skilfully made, with good production values, acting and script, but watching it I felt offended by the sloppy storyboarding and a lot of glitches and improbabilities in how this kind of thing could be carried out by a hired killer (the main police character was also much too obviously modeled on Garrison in JFK
, an incomparably better film).
As for jaunty preparations for the shooting, in one scene the guy tries to kill Palme by getting up on top of the roof of a (three or four storeys high) tenement house in a Stockholm suburb, in broad daylight, and gets ready to shoot the PM as he exits a tennis hall on the other side of the street after he's been exercising. The hitman mounts his rifle but breaks off the attempt when two women come up to hang some of their laundry to blow dry up there - this is absolutely inane, no pro killer hired for half a million bucks would ever try to do it that way, on the fuckin' roof of a peopled house, at very close range and in broad daylight. After the shots, he would have been unable to escape without far too grave risks. Just one of many examples. It was really plain that the film was sacrificing storyline logic and character credibility for cheap suspense effects and "what if they had only looked..." moments.
When I talked the film over a bit with some Americans online, I noticed they'd admit that it wasn't realistic, but they felt it was okay because those jumps in the logic made it look better, or funnier. They were aware that the film had been based on a real-life assassination, but to them it was really as fictional as Batman and reality didn't enter. To me, having grown up with the afternath of this particular killing and the suspicion, distrust and mystery generated by it, it was not something you could freely use for a popcorn flick. I recognized the need to make films about a subject like this one, but I felt that at least the first few had to be realistic in the sense that they didn't dabble around too far with what would be possible or likely - likely on the story's own terms. That film didn't take the trouble to do so and I felt offended and very dismissive about it.