I don't see it as a waste of a fight because I'll always want to encourage more options.
I suppose the way you could see them as being discouraged is them just not thinking about the importance of an easy mode. Now you say that they have thought about it and have decided against it which is probably true but people will continue to bring it up every time they release a game because they still think it's important regardless if From will ever heed it. Also there is active discouragement from the fanbase, it's why these threads always get so big. Although the time that Miyazaki claimed he thought about an easy mode was a mistranslation, this
article claims there was an uproar from fans afterwards and then the Metro quote claims that was a good thing. There is plenty discouragement.
I actually don't really disagree with your last point. It is a little unfair that From and their games keep getting dragged into these conversations; I'm not gonna claim that they're ableist because they don't have an easy mode. But they're mainstream games that are notorious for their difficulty. The conversation is gonna come up, it is inevitable. Maybe they shouldn't have had so much edgy lame ass "Prepare to die" taglines attached to their games if they didn't want people discussing the difficulty. And yes, we won't agree about an easy mode in these games being the same as accessibility and I certainly don't agree with the sanctity on the pure purposeful design argument because there are so many layers in between a creator's design and the way it's interacted with. Even if the accessibility conversation is unfair to From games, it constantly happening will show how important it is to many people and other developers will take note, even if From never will.