I could say (and have said) the exact same thing about Expert Mode. Which is my point: "fake difficulty" is an
opinion.
You consider the stat changes to Master Mode to be "fake difficulty". But you do not consider the stat changes to Expert Mode to be "fake difficulty". Maybe you excuse them because they also came with some AI changes, as if the two were inseparable rather than being separate design choices. Maybe you're fine with them because the stat changes are not extreme enough to cross some line for you.
Regardless of the reason why you accept it in one area and not another, what matters is that where that line gets drawn is ultimately an opinion. If someone else draws their line farther away and finds Master Mode's difficulty to not be "fake difficulty", that's their right. You can discuss where that line should be and why you feel Master Mode goes too far.
But you cannot simply state that your line is right and theirs is wrong as if it were an immutable fact.
You should take this as a lesson to pay more attention to what a feature is than how it is marketed.