I am with you on this. People, all people, want to be able to "explain" things, and sometimes it is a real stretch.
These professionals should know that sometimes the "trigger" is bio/chem/neurological, and not an external, or internal event. Hence, the efficacy of medication at times in the face of "events" "triggers". My moods also often have nothing to do with what is happening around me----even when I can pretend they do....
The question is: What can we do that will help? It may be behavioral (yoga, meditation if possible, physical exercise, biofeedback...hypnosis who knows) and the right medications. Practitioners often become frustrated when the patient doesn't "respond" ....
I empathize with you frustration, discouragement, and (I would think) anger with this dance. Perhaps you could provide them with some good literature/journal articles on the subject. (cheeky but hardly unreasonable)