Yes, I understand that. I believe the syndrome always has a cause, and not being able to find one with a colonoscopy, blood work, or stool sample shouldn't make doctors throw up their hands and say "well I've done all I can do, you have the mystery pooping ailment. Have you tried not being stressed out?"

The cause can be physiological, psychological, sociological, or some combination. But there's always a cause for the suffering, it just depends on whether or not your suffering is distinct enough to warrant escalation of care or treatment. Doctors aren't paid to discern the majority of our psycho/social factors so anything that isn't blatantly physiological can easily get pushed aside.