Could you explain how you don’t think mental health therapy is a science? We have psychology as a major in most universities, unlike chiropractic studies which are usually offered in different or specialized institutions. We have doctors of psychiatry that are actual doctors that can prescribe medications, just like general practice doctors. Therapy in different fields, whether it is in individual mental health or couple’s therapy are active areas of research in academia with published works you can read up on. So I’m not sure how you’re equating Mental health with Chiropractic practice.
It isn’t a placebo effect, as you mentioned. Therapy isn’t a cure/medication like drugs or a surgery for some diseases, therapy is more akin to exercising your mind so that you can face stress/fears/ any kind of emotional turbulence without losing it. Or as an avenue for personal growth or reducing effects of mental trauma. Saying it’s a placebo effect without backing it up could be actively harmful for people who might be considering it and actually need it. Yes, it’s not for everyone, and every therapists is different and every patient may or may not be willing to put in the work for it, but that doesn’t make it ineffective or a placebo effect. But how is that different from, say, how the covid vaccine affects one person vs the other (some experience more protection and/or suffer from mild symptoms for a couple of days, etc.) or how chemotherapy may work for some patients but not for others?
Why not both? We have the capacity to replace outdated/useless words and make the situation better for others. In fact, one does not prevent the other whatsoever