That feels like revisionist history to me. It rose to fame in LessWrong and SlateStarCodex, was promoted by Yudkowski, and proliferated for about a year and half before the takedowns finally got traction.
While it was the topic du jour in the rationalist spaces it was very difficult to argue against. I vividly remember how hard it was to convince anyone that SMTM wasn't a good source at the time, because so many people saw Yudkowski endorse it, saw Scott Alexander give it a shout out, and so on.
Now Yudkowski has gone back and edited his old endorsement, it has disappeared from the discourse, and many want to pretend the whole episode never happened.
> (I don't remember any detailed takedowns of SlimeMoldTimeMold coming before that article, but maybe there are).
Exactly my point. It was criticized widely outside of the rationalist community, but the takedowns were all dismissed because they weren't properly rationalist-coded. It finally took someone writing it up in the form of rationalist rhetoric and seeding it into LessWrong to break the spell.
This is the trend with rationalist-centric contrarianism: You have to code your articles with the correct prose, structure, and signs to get uptake in the rationalist community. Once you see it, it's hard to miss.