Extreme and entertaining are two different things. The idea is for the music to be uncomfortable at first, and then acquire a taste for it, to where future listens can be more entertaining. If someone finds favoritism with certain arrangement of low and high frequencies or like manner, and searches for future projects with a resemblance of sound, then they have found their box; their area, and therefore aren't looking for anything more challenging than their comfort zone. The reason I got into this music, and like I'd imagine for many others, it to get out of comfort zone. Also, if you use extreme music without extreme ideology, are you saying that if you did incorporate extreme ideology, then finished result as a whole wouldn't be more extreme?
Some of my most frequented Noise have been Mikko Aspa's projects, Deathkey/Intolitarian, Bizarre Uproar, Whitehouse, Ramleh, Prurient, Taint, etc. Yes, we can look 'Extreme' as extremely quiet, but the definition I used, is one that makes you out of your comfort zone. For some people, extremely quiet music can do that. In that case, it sees all interpretations of extreme (even though it seems there are universal themes, e.g. racism, child abuse, inaudible frequencies, which is more or less, what I'm focusing on. I'd reckon the more debased and 'unhuman' something can be looked at, defines its extremeness universally. What would be unhuman is something that doesn't remind of human events, either be it, frequencies so far removed from human vocal cord frequencies, and also message that is extremely antisocial, to the point where other antisocial messages seem tame, i.e. Rock music like Rolling Stones was once extreme, and is now tame and an acceptable form of human behavior in those lyrics.) can be valid., but only if it alienates and isolates someone from human existence, which quiet music easily could do, hence some more subtle and ambient frequencies in Delta range, or something. So, I'd imagine extreme quiet, and strange, and offensive, and harsh, generally all lead to same place, of extremely alienating, or in this case, just extreme.
What would be quiet, minimal, or harsh, or loud, and how which one leads to more alienating experience depends on listener's viewpoint of world and life experiences and preferences, but all ultimately meet at same, or so it seems, and the process of discovering objectively which goes the furthest (outside of humanness, i.e. more extreme) is what this very unplanned style of music is about.
Again, great suggestions. If anyone feels to challenge my claims, feel free to, or not. It's lead to an interesting discussion thus far, nonetheless, and I hope I did a good job at explaining the foundation of my post.
Lastly, if Rolling Stones was once most extreme, and now is looked at as tame music, why couldn't the same happen to Grunt or Intolitarian someday? It only seems like that it would be inevitable. If someone desires to create shocking music, does it necessarily mean they are personally offend by material they are 'against,' or they just exploring new concepts/themes/ideologies? If I make Anti-Christian song, am I personally offended by a sidewalk preacher?