Here is another article that completely misses the elephant in the room with regard to stress. The single biggest cause of destructive stress (yes, there is such a thing as constructive stress, for instance exercise and hard work) is having a person antipathetic to your survival either overtly criticising and invalidating you to your face or covertly undermining you by any means they can find. Optimal health is perpetually elusive if you are being beaten over the head with an emotional baseball bat!
Probably because they fail to recognise the existence of the human spirit and that the spirit is the principle healing agent of the body.