Yeah I think I focused on his generic Resident Evil in the first sentence and missed the RE4 nod at the end. Oops. Either way though, I think the point is solid... "the survival mechanisms aren't challenging enough therefore it isn't survival horror" is a silly argument. Difficulty does not define genre. For example, our beloved Deus Ex is not a hard game at all. Dump all your points into pistols and go around headshotting everyone and loading a quicksave when you miss, then post "this game is not an immersive sim because you don't really have to do anything else." Does that mean anything really, when it comes to how we define the game? RE4 has limited resources (even if you think there's too many), limited saving at specific spots, purposely less "action game" controls and a horror atmosphere. The genre that puts it in is pretty clear, even if it's an easy one of those.
Though honestly if the greater argument is that genre is a pointless construct at this point in gaming, I am very sympathetic to that argument. However if we're gonna call things "survival horror" games, then Dead Space and RE4 are in that category.
Difficulty is not where the argument lay. The so-called survival mechanisms are not implemented in a way that are in accord with the brand of "survival" established by the foundational game, nor are substantial enough to break the action game mold that some people put the game into.
And there are too many resources, so that you never have to worry about conserving for the future, avoiding enemies, or do anything besides killing everything, which the game is designed for you to do and is the antithesis of the "genre" defining game and how many people identify survival horror. And there are a number of full-stop action games where resources are finite.
There are only limited save slots. You can save as many times as you want. In the foundational game and following games in the same mold, saving is tied to a limited resource, which is tied to the limited inventory aspect
purposely less "action game" controls
But purposely more action game activity. And less action game controls than what? Not previous RE games or similar games from other developers.
and a horror atmosphere. The genre that puts it in is pretty clear, even if it's an easy one of those.
Yes, a horror themed action game. Looking at followups and influenced games also reveal this to be so. No one bats an eye when RE5 is labeled a shooter, when the difference is one of scale, not operation. It's a logical succession of the previous game. The logical succession of RE1 is...REmake, and maybe REmake2. RE influence gets you Silent Hill, RE4 influence gets you Gears of War.
Anyway, we all know the differences between each of the games and which one to go to for what we want, so arguing over labels is merely academic. Survival horror was a flimsy designation to begin with, and I never considered it a legit genre, more like a sub-category at best. The original RE was a horror themed adventure game. It was Maniac Mansion with weapons as part of your items suite. And Resident Evil doesn't even have a meaning anymore, it's whatever horror flavored product Capcom decides to ship with the title.
And genre is pointless, but not inherently. It's pointless because even if a genre were empirically defined, written down on meteorite by the hand of God, you'd still have people bucking against it because their pet game doesn't qualify, or some other selfish reason. We see this with RPG, where the fundamentals were codified years before the people who believe "you play a role in every game, so every game is RPG" were born. They have to believe this because they believe some genres are more prestigious than others, and who doesn't want their favoritest game to be seen as prestigious? Answer: Secure adults, but I digress.
Also the arbitrary splintering of genres into new genres because a particular game or series becomes popular and spawns imitators, unnecessarily clutters things. Survival Horror is one, but that's even better than Souls-like and Metroidvania, which are just a style of Action RPG and Action-Adventure, respectively. Imagine if we did that for every somewhat unique game that had imitators. Half-Likes, MarioSonics, StarCraft & Conquers, etc. Only legit exception is (traditional) Roguelikes, which are basically RPGs, but it's like a warning of permadeath, RNG screwing you over, and ensuing butthurt.
Basically the problem with genre is emotion-driven dummies having a say in the matter, like everything else.