It's a respected field here, (obviously not universally well respected) although not as highly paid as anything requiring med school.

It's just a way for people with well paying STEM degrees and jobs to look down on people who make different life choices.

A title being protected doesn't mean it's scientific. C.f. naturopathic "doctors."

I don't know enough about art therapy to say that it is or isn't scientific, though.

Art therapists are licensed therapists who focus on treating patients in the way the title implies. I don't think I'd call it science, although the one graduate program I'm familiar with has their students treat children and report on the efficacy of the results.

It's often an MA degree, so there's no pretense of it being a scientific endeavor.

In what way is therapy not science?

I don't think most therapists publish much, is the short answer. For a more meaningful answer you'd want to ask a practitioner, I would think.

I'm assuming that art therapy is grounded in a scientific understanding of psychotherapy. You don't need to be a professional scientific researcher to practice science.

I realize that my wording was ambiguous so I'm sorry for that.

What is a "protected title" in the UK?

You can't call yourself a protected title unless you have the qualification and professional registration.

Here's a list for health care: https://www.hpc-uk.org/aboutregistration/protectedtitles/

Thank you for the clarification.