You just did this exact thing to Heels for like 3 posts in a row...
Having read all of your examples I still don't see why any of the implementations of difficulty you have mentioned would be considered 'artificial'. That is the part you need to define. Artificial seems to indicate that it acts outside of the bounds of some form of 'true' difficulty. If player skill is the determining factor for what determines 'true difficulty' then you have to find something that isn't a learned skill that is being tested by a map to call it 'artificial'. Foreknowledge is a skill because it involves learning the layout of the map (to say otherwise is to say that speedrunning in general is not skilful). RNG is a factor that is outside of the player's control but dealing with and mitigating RNG is still a skill - or dealing with the challenges that are put forward by RNG.
I think a lot of what players determine as 'artificial difficulty' relies on their own presuppositions of what difficulty is supposed to be. This is the problem. The supposed 'objective term' is based on a number of subjective factors. It's ridiculous to determine this as 'objective', as if difficulty is some Platonic ideal that exists irrespective of human bias. You have your own personal assessment of what 'true' difficulty is and you are going into a mapset with that in mind, then it angers you when you die to things you perceive to exist outside of those truths.
The fact is, 'artificial' isn't useful as a descriptor at all. Every mapper has their own definition of difficulty and so does every player. The problem seems to be when those two perceptions don't align, one of the two -usually the player- decries the other for being 'wrong' about what difficulty is. There is a reason Ribbiks constantly has to tell people not to play his wads on UV, because everyone has a preconceived idea of what UV is 'supposed to be' and it is very different to what he wants UV to be. These preconceived notions of what UV is 'supposed to be' need to go away so that mappers can feel free to experiment without being told they are 'wrong' when making wads that are of a difficulty level that they -and a lot of others- enjoy.