So you're not reading what I'm writing, or not understanding it? A trial versus placebo allows you to test whether people feel better because of a practice, or just because they convinced themselves they feel better. If any dude that pretends to be a shaman has the same positive effect as an actual shaman, then shamanism is bullshit. It's as simple as it gets.
The study you linked is basically just a summary of a bunch of papers that contain extremely small sample sizes (one person for most of them), no comparison with placebo, and the conclusion is "our sources are very unreliable, people's beliefs in shamanism matter heavily for it to work, and overall we can't be sure that it works, but it could be worth looking into". It means absolutely nothing at all, if anything, it means that it's unlikely that shamanism has anymore healing properties than any other magical belief.