But "organic XP accumulation" doesn't remove grinding. In fact, it increases it, because unless you're playing in some sort of Skyrim-esque sandbox with random quest generation, quests are limited. You will run out. The common definition of "grinding" in an RPG implies taking advantage of some kind of unlimited procedurally generated generic source of experience, such as respawning monsters for combat XP grinding. For the ultimate example of how "organic XP accumulation" facilitates grinding, go watch a video of somebody jumping around for an hour in an Elder Scrolls game to grind their Acrobatics skill. You're both giving the player more sources of experience to grind, AND those sources are more likely to be inexhaustible.
I don't agree that the source of XP needs to be unlimited, grinding is about the experience of the player, it has little to do with XP being limited or unlimited. For example, there is a maximum amount of XP to be gained from every area in Lords of Xulima, but if you roam around every area doing total area clears to maximize your XP gain, you are obviously grinding.
Also, can you really describe the fundamental thing that story-driven RPGs are composed of as "grinding and not playing"? The typical RPG nowadays is essentially a series of quests. You start at the beginning of a "main quest", and do a series of sub-quests within the main quest until you do the last sub-quest and finish the game. Progression in the game is fundamentally defined by doing quests, not by accumulating XP. Saying that a story-driven RPG encourages "quest grinding" is like saying that a beat-em-up encourages "punch grinding" or a first person shooter encourages "shoot grinding". It's kind of missing the point.
If you fundamentally enjoy doing each and every quest in every game, then you might perhaps be beyond finding such an experience "grindy". But if you like to actually ROLEPLAY your character, choosing which quests you do or do not want to undertake, or you simply like to be able to skip whatever content is uninteresting to you, then being forced into doing all quests because that is the only way to build your character is certainly going to feel tedious, restrictive and grindy.
Furthermore, with quests, each source of XP is a unique scripted event, not a generic thing that you can do. "Grinding" also typically implies a boring, repetitive series of actions designed to extract XP out of the game in a rote fashion. But since quests in a story-driven RPG are unique, then if they're well designed, the player won't feel like he's "grinding" anything.
Again, "grind" is something experienced by the player, and it can be experienced regardless of whether the content is generic or unique, as long as you are forced into particular patterns of behaviour in order to accumulate rewards such as XP, reputation, loot, etc.
tl;dr "Quest grinding" isn't actually a thing that exists in this sort of game, and it's funny to me how the SitS team keeps throwing these out-of-context bones at PoE's upset grognard crowd
Of course it does, you may not experience it due to how you prefer to play these games (roleplaying a slavish "yes boy", agreeing to do everything everyone tells you) but not everyone is interested in that particular way of playing RPGs. I for one highly value being able to skip content that I find uninteresting or contrary to my play style or roleplaying decisions.
I don't think that the SITS couple are merely throwing bones at grognards. In fact it is rather telling that low ego developers such as the SITS couple recognize that this is an issue that exists, and are designing their game to avoid inflicting quest grinding on their players. You have to keep in mind that the Obsiidian guys such as Sawyer think they are auteurs of some sort after receiving years of fellatio from fans, and it is their inflated egos that makes them think that they have the right to dictate the experience of their players, that they exclusively know what is or isn't fun. Hence quest grinding, forced autoresurrection, no hard counters, trying to reverse engineer how RPGs are played, etc etc. The cool dudes behind SITS are just letting players know that rather than taking that approach, they will instead let players define their own experience with the game, play it how they actually want to and have fun with whatever they actually find to be fun.