You guys have a huge celebrity culture and add that the the importance of the reference element in general culture, it is inevitable that characters like these will become history in many different context.
This Truman guy. I had no idea who he was before reading this thread, but my first impression was 'ah he wanted to go with a bang'. Because honestly, it looks like that from what was posted here, but the reading his wiki page makes you sure about it. He was in WWI, came back worked a lot of different jobs, married a few times, lived in there for 52 years. He is bootlegger and a prospecter.
He is one of those people who are avoided as 'the village idiot', but sounds like a bit more crazy than idiot because he sounds like a conman and mentally unstable too. (Apparently, he wanted to throw his first wife into the lake although he knew she can't swim. Could be a rumour. Nohing happened.) Anyway, he looks like a bad prankster too, someone who did reckless, dangerous stuff. ...
America is very suitable with everything it has for this kind of a man to be recorded as a 'folk hero' esp. considering the times. Vast space, nature, too many place to be territorial, not enough people to stop it, lol. There is nothing on the land. An old stubborn man; a soldier (a war hero ), a bootlegger, a treasure hunter... headbutting authority for his mountain and literally dies on the hill.

Obviously, after becoming a minor celebrity when this happened, as he was very old, he wanted to die as one. It also looks like his family pushed the stories after his death too. Yeah..
I think it annoys you because it is perpetuated by being replaced in bigger contexts. It's nothing but a loud exit.