/snip
So TL;DR: what I disagree with is dogmatic assertions about how things have to be in RPGing in general; and that 4e D&D has to be absurd or contradictory or laden with "cognitive gaps" in a way that AD&D is not.
The issue is, you're missing the point. They aren't saying that this is how RPG's
have to be. They're saying that, in their mind, it's self evident that that's what RPG's
are. So when you talk about how you interpret the game, it doesn't matter what evidence you bring forward. They will not ever accept that their interpretation is flawed, any more than you will accept that your interpretation is flawed. It doesn't matter how many Gygax quotes you throw at them. They have created this interpretation for how D&D (specifically) works. They can't really conceive of it not working this way because they have constructed the language they use surrounding the game where that interpretation is central to how they view D&D.
So, in that interpretation, it is the role of the game to define the fiction. It doesn't matter that you find this contradictory. In their interpretation, the narrative is fixed before hand. So, all weapon damage deals some injury. Any effect which cannot be directly correlated from the mechanics to the fiction is either ignored or rejected. So, a successful attack always strikes the target, always dealing some sort of injury and anything that deviates from that interpretation is either an outlier (dying from ingested poison where the character is dead with full HP, nary a wound to be found) or safely ignored.
And nothing you can say will change that. The argument against you is unassailable behind a high wall of "well, that's my playstyle". And, frankly, because they are every bit a part of the D&D community as you or I, we can't really gainsay that.
Until such time as some sort of compromise is made to bridge the different interpretations, there was simply no going forward. Which is frankly, where 5e comes in. You see it in how people talk about it as having stuff that they maybe don't like, but, not so much as to "break the camel's back". So, it's okay to have non-magical healing with fighters, and non-magical healing overnight. It's the compromise. It's maybe objectionable, but, not so much as to actually push people away.
And, now, with so many new players out there, all us old buggers who might care about this, are becoming more and more irrelevant. The "overnight healing" is the way D&D works. So on and so forth.