Whatever the Forge people might say, Gamers have agendas. Games are tools we can use to fulfill agendas.
I know some folks say that a given gamer only ever has one agenda. I think that's silly.
The Forge people don't dispute that a single person can enjoy different things. And they certainly don't dispute that a given game can serve different agendas (Champions and Tunnels & Trolls are two mainstream games often mentioned in this context).
They tend to favour "tight" design that focuses a game in on one particular agenda, but that's a design norm, not a prediction about extent rulebooks and the uses to which they are being put.
Some games, therefore, are designed to fulfill multiple agendas.
I think the main question is, can you fulfill multiple agendas all at once? The Forge says "no". The argument, at least as I understand it, goes roughly like this:
* An agenda is about the point of play, as manifested through the sort of behaviour at a given table that is encouraged or discouraged.
* During a given episode of play, it can't be that - at one and the same time - participants are (say) encouraged to subordinate "gutsiness" to fidelity to character and setting concepts, and acclaimed by their felllows for gutsy play.
* Therefore (generailsing the above premise to other differences of agenda), during a given episode of play only one agenda can be pursued.
I think that there are at least a couple of points where the argument is vulnerable.
One is this: while it is plausible as an argument that simulationinst and non-simulationinst agendas aren't compatible (and I regard this as borne out by practically every thread I've participated on these boards where the contrast between "mainstream D&D" and "indie" play agendas has been discussed!), I'm less sure it is plausible for multiple non-simulatoninst agendas. For instance, it seems to me that, during a given episode of play, it perhaps can be that - at one and the same time - participants are encouraged to play their PCs to the hilt so as to drive conflict to its resolution,
and are acclaimed by their fellows for gutsy play. Particularly if the system is designed to require gutsy play as a necessary mechanical condition of driving conflict to its resolution. (Burning Wheel might be an example of this.)
A second point of vulnerability, and I think one that a lot of people (perhaps including Umbran?) have in mind, is to question the monolithic nature of the group.
I think the idea is that you have one participant who derives pleasure from subordinating "gutsiness" to fidelity to character and setting, and another participant who derives pleasure from playing in a gutsy style. WotC seems to favour this sort of idea, with its discussion of "player types" in its DMGs (derived, at least loosely, from Robin Laws' similar ideas, I think). In D&D, in particular, this tends to be achieved by making one aspect of the fiction - combat - the site for gutsy play, and another aspect of the fiction - social encounters and urban exploration more generally - the site for subordinating gutsiness to fidelity to character and setting. (Mearls certainly echoed these divisions in contrasting combat with "roleplaying". You also see it in the frequently-expressed idea that combat is an alternative to, rather than a site of, characterisation and roleplaying.)
The Forge response to this rebuttal of the "single agenda" argument, and one for which I personally have some sympathy, is that a game in which you have participants looking for different things in this way, is in some sense unstable or "second best". It relies on a high degree of GM control over the game in order for it to work, and is vulnerable to player disruption at many points (most notoriously, the "power gamers" or "munchkins" who try and turn social encounters into combat encounters, or who build PCs that run roughshod over the "roleplayers'" PCs in circumstances where resolution via mechanics, rather than via free roleplaying and GM fiat, is involved).
I think this, as much as the jargon, is why The Forge is regarded as elitist: because the core implication of The Forge's analysis, as I've just sketched it, is that mainstream roleplaying - in which the GM exercises a high degree of control to make sure everyone gets a little bit of what they like, and which is vulnerable to disruption by "power gamers" and "munchkins" - is inherently unsatisfactory. (Or, at least, less than fully satisfactory.)
A second implciation, somewhat relevant to the idea of "stewardship", is that roleplaying would be more appealing to more people if it didn't, at least in its mainstream form, take for granted this rather specific social contract in which people agree to subordinate their own aesthetic preferences for those of others in this systematic yet somewhat arbitrarily adjudicated way.
I entirely disagree that there's any particular edition of D&D which is more gamist than any other. Some fake simulationist ideas, but faking it and being it are very different things.
How can you fake simulation?
An example from 3E/PF - introduce the notion of "natural armour" bonus.
Ancient and older dragons have natural armour bonuses somewhere between +29 and +40. A Pit Fiend has a natural armour bonus of +23. This is in circumstances where the most magical of all suits of plate armour grants a bonus to AC of +13. What do those "natural armour" bonuses represent, in the fiction? No one knows, or bothers trying to find out. There are simply mechanical contrivances to ensure CR-appropriate ACs, with a veneer of simulation applied via the "natural armour" label.
Another goes back much further in the game: label a spell that heals a lot of hit points "Cure Critical Wounds" even though there are plenty of critical wounds that can be healed by much weaker spells (eg "Cure Light Wounds" will probably heal any critical wound suffered by a 0-level NPC), and there are plenty of non-critical wounds (like a dragon bite suffered by an otherwise-uninjured high level fighter) which cannot be healed by a single application of any lesser spell.
Once again, what we have here is a mechanical contrivance for the rationing of hit point recovery, with a veneer of simulation applied via the "Cure Critical Wounds" label.
In the context of D&D, I think the most obvious examples tend to come from the combat mechanics, but they can be found elsewhere as well - for instance, the various bonus types in 3E like "sacred bonus", "insight bonus", "luck bonus", "circumstance bonus", "competence bonus", etc - it's quite unclear to me what these all correspond to in the game. How is a sacred bonus - which sounds to me like a blessing from the gods - different from a luck bonus - which sounds like it might be the result of a blessing from the gods? Or how is a luck bonus - which sounds like it might be about fortuitous circumstances - different from a circumstance bonus - which presumably reflects fortuitous circumstances? How does "insight" differ from either "luck" or "competence"? Etc. Once again, no real effort is made to give these notions an ingame meaning. They're mechanical contrivances with labels slapped onto them to create the veneer of simulation.
This is the sort of thing that a lot of people have in mind, I think, when they describe 3E as an "illusionist" game, or describe 4e as - by way of contrast - having "drawn back the curtain". (The Forge also uses the term "illusionism", but to describe something quite different from this fake simulation.)