I suspect the response varies greatly by individuals: some respond a lot and some don't respond at all.
My experience with SSRIs was very positive. I took a low dose for depression for a few years and it helped significantly. I went off it a few years ago and my depression hasn't returned.
That study found a small effect size compared to placebo, and a large placebo response.
That seems consistent with OP's comment of "SSRIs...mostly don't differ from placebo" (emph added).
Also not addressed in the paper is the fact that SSRIs and SNRIs have well-known and pronounced side effects, with make it questionable whether double-blind studies are really fully blinded.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5667359/
I suspect the response varies greatly by individuals: some respond a lot and some don't respond at all.
My experience with SSRIs was very positive. I took a low dose for depression for a few years and it helped significantly. I went off it a few years ago and my depression hasn't returned.