Basically, it all started with the theory of co-op games, where mechanics took a back seat to player interaction, the lack of a need for a GM, stuff like that.
I stayed out of most of it, because to me it looked like a fountain of faggotry.
From there, you spawned a couple of superstars, most of which I don't even remember. One guy built The RPGSite IIRC.
The whole thing started with "We need more inclusive language, stop using him/her and use them more!" and then complaints about big tittied chicks and Conan-esque dudes with "They don't represent the people in the hobby and make people feel unwelcome" about 2002. ENWorld was a positive seething mass of this shit, mainly around one guy's advertisements.
You had the typical superstars out championing for the Right Way the Hobby Should Be Played.
(Funny thing, I know for a fact that at least 1 of the superstars went to jail for child porn, at least 2 others embezzled funds, and one major company didn't pay out their contributors since the guy who ended up with the company didn't feel the need to pay any of the authors the child porn dude hired)
Then there was the big shit-fit about Anthony Valterra putting out the Book of Erotic Fantasy, which led to a change in the STL with Wizards, which just gave the Forge crowd more ammunition.
It became very quick: This is the proper way to play.
One game in particular, maybe two, were linchpins: My Life With Master, and Dogs in the Vineyard (I never looked at either, I was busy). Which were all about inclusion and player choice with limited rules.
The Forge were advocating for getting rid of random scores, ensuring everything was perfectly balanced, and there was talk of reducing ability scores to just the bonuses, so it would run -4 to +4 only.
"Narrative Gameplay" was thrown around a lot.
One game, all I remember was it had a fucking magic deer, was called Blue Rose, and this caused an even bigger shit storm.
Now, remember, this was in the days before YouTube streamers so it was just long ranting screeds and posts. Most of the sites are gone, and ENWorld suffered a server crash which wiped away a lot of shit.
This was the whole early 3.0/3.5, which was just a tsunami of spergery about everything.
Then 4.0 came, Pathfinder happened, and everything crashed for a lot of people. Most of the people faded out.
Some went into video game design, including one person who was tangentially involved in the Forge Wars but then was a big name in Gamergate, I shit you not.
Now, like Gamergate, it's already been fought, only in the case of TTRPGs, for the most part, the gamers who built the game, who supported the companies before they got big, they got colonized and wiped out in purges.
It was all just cheeto dust in the wind.