The Souls games are a terrible example of this. The quality of those games is largely reliant on the ability to have fun by getting over difficulty curves. If someone played a Souls game on easy not only would they miss the point of the game largely, but they would probably enjoy it less too. Not every game is for everyone - and one thing that sticks out about the example regarding the Souls games is that it's never a wish of the developers or the fanbase for there to be an easy mode, it's always the wish of people the game was never catering to to begin with. At least with the Nintendo games you gave as an example it is an actual want of the developers to provide player assist.
The other games you listed had no real outrage as to their player assist so I don't really know what you mean? I do know that people would mention how they didn't like using the mode, but then they just wouldn't use it. The most recent example of outrage might be Mario Kart 8 Deluxe, but that was because that game can be quite competitive and allowing an AI to help the player steer can potentially be frustrating for other players. Though, I've never seen anyone actually complain about it's use, just the theory around the idea, and so again on that end there wasn't a big outrage about it.
There are ways around this though. I dont think there is any justification for agame not having difficulty settings And this is coming from someone that selects the hard difficulty on every game I play.
Just award a trophy for finishing the game n the hard difficulty. Maybe even throw in a special ending there too. This way those wanting to experience a game as intended can and those wanting an easier playthrough can also play too. Everyone wins.
Take GOW for instance. One of the hardest games to play on Give me God of war (hardest) difficulty and they also made it so that its the one difficulty you can't change mid game. Didn't stop millions from loving the game.