Look, I understand that you want to see dissociated mechanics everywhere because it's annoying to read it about 4e, but then again, this is not the case.
In-universe, you spend different resources, as an example, to write a scroll of level 1 compared to level 6. The difference exists there even ignoring other factors like the level of knowledge and power required to cast them. Certain spells ARE more powerful and even if the creature in the world don't call it (again) "level", the difference exists in-universe.
So a monster that is outright immune to a spell below a certain power which we conveniently call "level" is not dissociated. I would recommend to do not point and scream "dissociated" at everything that moves in the near future just because the word annoys you.