As I'm about to demonstrate, they are also in contradiction to Gygax's DMG and to Moldvay Basic.Your statements about the role of the DM are in flat contradiction to every DMG from 2E onwards.
Also, are you familiar with the early 80s Puffin book "What is Dungeons & Dragons?" (Americans generally aren't, but as a British RPGer you might be)? It includes examples of player-created fictional background, players making decisions for their PCs based on ingame story and thematic concerns rather than simply pawn stance, and certainly has a far more expansive conception of what RPGing might be then is demonstrated in howandwhy99's posts.
From Moldvay Basic, p B53:DMs are referees in that they only convey the current set up. They don't get to choose to manipulate it like a player.
Initial conditions, like any rule, is set before play begins. Improvising behind the screen robs players of being able to actually play a game.
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wandering monsters are rolled, not made up by the DM.
Wandering monters may be determined at random or selected by the DM. . . Wandering Monsters should apppear more often if the party is making a lot of noise or light, but should not be frequent if the party spend a long time in one out-of-the-way place (if they stop in a room for the night, for example).
From Gygax's DMG, p 221:
Some Dungeon Masters have difficulty decribing the contents of potion bottles, magical elixers, and like liquid substances. The lists below give the appearances of liquids, colors, tastes, and smells. In combination with APPENDIX I: DUNGEON DRESSING (q.v.) or by itself, these various descriptive words will serve the DM in god tea when preparing level keys or when "winging it".
Gygax again, p 110:
t is your right to conrol the dice at any time and to roll the dice for the players. . . You might . . . wish to give them an edge in finding a particular clue, e.g. a secret door that leads to a complex of monsters and treasures that will be especially entertaining. You do have every right to overrule the dice at any time if there is a particular course of events that you would like to have occur.
It seems to me that neither Gygax nor Moldvay agrees with you. I have my own views on what sort of "overruling" Gygax had in mind - I think he was not talking about Rule 0 or cheating, but about GM control over framing and also the adjudication of fictional positioning - but it is clear that he thinks a GM has a role to play in introducing and managing game content during the course of play.
Relating back to my OP, Gygax also advised (on p 110) that
There will be times in which the rules to not cover a specific action that a player will attempt. In such situations, instead of being forced to make a decision, take the option to allow the dice to control the situation. This can be done by assigning a reasonable probability to an event then letting the player dice to see if he or she can make that percentage. You can weigh the dice in any way so as to give the advantage to either the player character or the non-player character, whichever seems more correct and logical to you while being fair to both sides.