There's a lot of dismissiveness here. What I don't see, so far, is even one comment actually engaging with the statistical analyses that are the heart of the article. (Maybe one's being written by someone else while I write this.)

I assume most people here are very skeptical about homeopathy. And yet, there are plenty of statistical studies that "show" that it works. The interesting thing about them is that the more rigorously the studies are done in terms of conforming to best practices for minimizing the risks of confounding errors, the smaller the statistical affects are, until they get to near zero for the most rigorous ones. Which is exactly what you'd expect to see if the effects of homeopathy are actually nonexistent other than placebo. Which I believe them to be, since the "theory" behind homeopathy makes no sense at all to me.

The article we're discussing here purports to show a similar thing: Studies that correct for more confounding factors show smaller effects. I can't judge how factually true analyses found in this article are; the writers may be making it all up. On the other hand, it could be a mistake to dismiss it out of hand just because its conclusions are not consistent with today's common wisdom. Also, we should note that anecdotal reports from individuals, here or elsewhere, about what good it has done them don't disprove the author's point. Psychotherapy can work for some people but still not have a great average effect size.

Personally, I'd be very surprised if psychotherapy is actually worthless on average, although I think that the therapy I had in my late teens and 20's, for years, probably did me more harm than good, other than just having a group therapy group to talk to. Which WAS valuable. But most of the good came just from talking to other people who happened to be in the group, not from the therapist. (I had individual and group therapies during that period. I think the individual therapy was probably worth less than nothing; there were definitely harmful things that came out of it that I am very clear on decades later.) But my personal story is just another anecdote. It seems logical that if someone is trained in helping, and someone wants to be helped, then on average there would be positive results.

But they may not be as much as is commonly thought to be the case in today's world.