How does it relate to the fact they all do mistakes?
Action of chiropractor is a mean to correct imbalance in the body. Most of the time it works, sometimes not. I would call it side effect, which any evidence-based pill has also.
The problem is that there is no expectation for a chiropractic treatment to be effective in solving any problem, since chiropractic is not evidence based. However there is evidence to show that there are significant risks of injury to undergoing chiropractic treatments.
Acupuncture, massage, biofeedback therapy, laser therapy, electrical nerve stimulation and other nonsurgical spine treatments