I completely agree with you, but our society has such a stigma around mental illness that if you tell someone their back pain is caused by repressed emotions, you get what happens in the article.
But...you would (or could?, or should?) never tell someone that, because how would you know? Maybe there is some link but to conclude that it could be the case is pretty silly.
So it's not like that's a stigma, it's just a statement not based in fact that evokes a strong reaction because you're telling someone why they're feeling a certain way when in reality you have no idea at all.
As another example, stress was blamed as the main cause of ulcers for decades, when an H pylori infection turned out to be the primary culprit.
Only the good things, of course, because they are all angels.
You are the reason why such reactions occur.
I think the main problem with many doctors is the fact that the patient tends to feel blamed when told that their minds are causing the problem. This is not Sarno’s approach at all, since he states that chronic pain can be seen as a defense mechanism against deep negative emotions.