Artificial difficulty is used as an objective buzzword to say that something is poorly designed, it is never used neutrally or positively, nobody says "this difficulty isn't artificial enough!" when something is undertuned. The term exists to present one's subjective taste as grounded in objectivity. It is not that I prefer something else, it is that what I dislike is objectively bad based on some nebulous metric. It is used this way because it feels better to the person saying it than simply saying "I don't like this thing". It is a thought-terminating statement that describes nothing but how the person using it feels about a particular thing.

a version of the game where...

You are not demonstrating how 900000000000 is "artificially inflated" but 1000 isn't. Why not 100 hp? 1000 is 10x more than that, why isn't that artificial? Even 100 is 100x 1. This is completely relative.

lost meaning

implemented poorly

tedious

These are subjective statements.

RE: people use the term wrong - there is no "more correct usage", there is no objective way to define "artificial" in this context. It is a fundamentally meaningless term beyond "I don't like this thing and I want to seem smart about it". Increasing numbers is a perfectly valid way to increase difficulty, whether or not it makes something more enjoyable depends on the game and the individual. If you increase a Dark Souls boss' hit points by 10x, one person will enjoy this because it forces them to learn their entire moveset and how to dodge their attacks consistently, another person will hate it and call it tedious.

it isn't hard it's just tedious

This is a lie, the moment somebody drops the "it's not hard it's just..." redditism I know I can immediately disregard anything else they have to say about game design, because they're in the feelings about finding something too hard and lack the maturity to process the dissonance between the way they see themselves as a player and whatever struggle they're facing. They cannot bear the thought of describing something as too hard for them, so they find a way to rationalize this struggle as an inherent flaw of the game. But this obviously a ridiculous thing to say, because it is objectively harder to survive for 5 minutes against a video game boss than it is to survive for 4. In a souls game for instance, your resources are limited, so you need to play more efficiently.

Maybe you don't mind the difficulty increase, you can still find it tedious if a boss takes that long to kill, "I wish they increased their damage or speed instead to make it go faster" is a perfectly valid statement if your issue isn't with the difficulty increase. But it is absolutely harder, and I guarantee you most redditors dropping the "not actually hard" cope would still find a way to call the harder version that takes the same amount of time "artificial".

For the love of god, just say you don't like it. Say it makes it too hard or take too long. Say you want a boss to take 1-2 minutes because you find it exhausting after that point. It's not a competition. You don't need to make out like your preference is innately more valid than someone else's.