one purpose of criticism is to try to find new meaning of conventional thought or a thought that seems to be wrong, not just to say something is wrong. so, this is a really good topic.
in my understanding, non-linearity is about the relationship between events/phenomenon.
Good non-linearity, i think, doesn't have predetermined axis for evaluation. The axis might be 'timeline'. It might be 'location'. Those axis limits or gives some kind of a constraint to reader. As opposed to the linearity, what you have in non-linearity is just a cloud of events/information that you can freely evaluate with your own measurement. That's why interactivity and non-linear have many things in common, in my understanding.