Erik Tenkar has been writing guides to the OSR games out there. For his trouble, he's being accused of historical revisionism by the "RPG Pundit," a person who you may remember from "consultant-gate." Erik's post about it is here. I won't link to the Pundit's site but you can find the post by Googling his pseudonym.
The attack on Tenkar is based on the idea that the early / close retro-clones weren't really the font from which the old school renaissance came. Which is malarkey. The OSR became a single thing in 2009, when Dan Proctor made it one.
A history of the OSR can start in dozens of places. You can start in Dragonsfoot, with gamers who never really stopped playing AD&D or B/X D&D getting together to talk shop. Or you can start with Hackmaster, which put 1e back into print (albeit in a strangely modified form). Or with Castles & Crusades, which created a lot of the pressure for these games. Or you could look at Necromancer Games with its "First Edition Feel" and 3e reprints of Judges Guild products, or Goodman Games's Dungeon Crawl Classics series. Or you could look at WotC's early PDF releases, which included OD&D for a hot minute.
There were literally dozens of things contributing to an old school explosion in the mid-2000s. The RPG Pundit bizarrely chooses to look at two oddball projects. One, Mazes & Minotaurs, was an attempt to imagine what D&D might have been like with an ancient Greek flavor. The other, Encounter Critical, was an attempt to pawn off a fake late '70s RPG. EC has had some influence on the OSR, because Jeff Rients loves the thing. But I've never detected any real influence coming from M&M, and as someone who minored in ancient Greek and Roman history in college, I would be able to tell.
The problem with looking at it from the influences is that events like the OSR are not unitary things. No single event happened and then the OSR was on; it was more that several things were happening in parallel, and they only happened to be grouped together later. The old school buildup wasn't a single powder keg; it was several smaller fires that later merged, and later still drifted apart in ways.
But the most important events were the publication of BFRPG and OSRIC, because they changed things fundamentally. Once BFRPG and AA#1 Pod-Caverns of the Sinister Shroom were in print, there were now rules and adventures resembling those of the late 1970s and early 1980s, with no apologies, no parody elements, no conversion to 3e or a "modernized" system. RPG products that were old school as a badge of pride.
OSRIC and BFRPG were fundamentally different. OSRIC was something of a fig-leaf, a system designed to be indistinguishable from AD&D so that you could use modules for OSRIC with your AD&D books with no conversion. There was no assuption that people would play OSRIC; in fact, there were at least 20 modules released before it was available in print. BFRPG, by contrast, was a community project meant to be played, B/X with a light clean-up to a few rules.
What was important was that the barrier was breached in the summer of 2006, and that's when the flood of material that we can now identify as part of the OSR started to happen. The Hoard & Horde spreadsheet by Guy Fullerton makes it abundantly clear that things changed significantly at that exact point in time. Any history that doesn't frankly say that before BFRPG and OSRIC there wasn't what we identify today as OSR publication, and afterward there is, is being revisionist.
The derisive mentions of "clone-mania" and "Talmudic" interpretation of rules and Gygaxian minutiae make it quite clear what the Pundit's revisionist agenda is. He doesn't like the wing of the OSR represented by that play style, that sticks close to the old games instead of remixing them and re-imagining them. Ironically this misses a big chunk of the point of OSRIC and BFRPG, which has always been to get adventures and support material out there for these older systems. There are three hardback collections on my shelf of Advanced Adventures collections; each contains 10 complete OSRIC modules. BFRPG just released a book of adventures in print. Neither gives much of a damn about history or precise accuracy.
BFRPG wanted to get people playing old school B/X style games again, and it succeeded. OSRIC wanted to get new support material for original AD&D, and it succeeded. These are admirable goals, rooted in actual play and the continuity of a gaming community that are worthwhile in themselves. The OSR should be proud to say these games are where our prehistory ends and our history begins.