Its because you have to be old and into computers at a time when no one was into computers. Just geeks..
I remember the demoscene because I was downloading since 1983 and usually games included the cracking groups demo. Yeeeears ago....
Yes the demo is a very old culture. In 1983, I have not even been born yet. I did not see those years. But as a programmer, this culture affects me. Things that programmers at that time are doing on computers with limited capacity are of my interest.
In those years, the crackers put their own intros in the entry parts of their programs. It was like a kind of hull show. Later, instead of crack the program, preparing a demoscene turned into a more enjoyable ego race.
When they make a documentary about a Demo, it is THE demo!
Thanks for sharing. A nice demo of the Razor1911 group -> https://www.youtube.com/watch?v=xi5Awxd_9DY