> That post came out a year later [...] multiple links showing how much the SMTM post was spreading through the rationalist community with little question.
The SMTM series started in July 2021 and finished in November 2021; there was also a paper, similar enough that I assume it's by the same people, from July 2021. The first of those "multiple links" is from July 2021, but the second is from January 2022 and the third from May 2022. The critical post is from June 2022. I agree it's a year later than something but I'm not seeing that the SMTM theory was "spreading ... with little question" a year before it.
The "multiple links" you mention -- the actual number is three -- are the two I mentioned before and a third that (my apologies!) I had somehow not noticed. That third one is at +74 karma, again much lower than the later critical post, and it doesn't endorse the lithium theory.
The one written by E.Y. is the second. Quite aside from the later disclaimer, it's hardly an uncritical endorsement: "you are still probably saying "Wait, lithium?" This is still mostly my own reaction, honestly." and "low-probability massive-high-value gamble".
What about the first post? That one's pretty positive, but to me it reads as "here's an interesting theory; it sounds plausible to me but I am not an expert" rather than "here's a theory that is probably right", still less "here's a theory that is definitely right".
The comments, likewise, don't look to me like lockstep uncritical acceptance. I see "here are some interesting experiments one could do to check this" and "something like this seems plausible but I bet the actual culprit is vegetable oils" and "something like this seems plausible but I bet the actual culprit is rising CO2 levels" and "I bet it's corn somehow" and "quite convincing but didn't really rule out the obvious rival hypothesis" and so forth; I don't think a single one of the comments is straightforwardly agreeing with the theory.
If you've found something Scott Alexander wrote about this then I'd be interested to see it. All I found was that (contrary to what you claimed above) it looks like ACX Grants declined to fund exploration of the lithium theory but included that proposal in a list of "interesting things we didn't fund".
So I'm just not seeing this lockstep thing you claim. Maybe I'm looking in the wrong places. The specific things you've cited don't seem like they support it: you said there was an ACX grant but there wasn't; you say the links in the intro to that critical post show the theory spreading with little question, but what they actually show is one person saying "here's an interesting theory but I'm not an expert", E.Y. saying "here's a theory that's probably wrong but worth looking into" (and later changing his mind), and another person saying "I put together some data that might be relevant"; in every case the comments are full of people not agreeing with the lithium theory.