Is 'human error' ever acceptable as a cause? My personal opinion about the topic is that any human error has a cause. Unless the person sets out to injure themselves, the reasons can be almost infinite. From lack of knowledge, to work pressure, lack of tools or equipment, stress, distraction and simply not enough physical safeguards. Humans don't normally behave in a random way unless the brain has a fault that triggers illogical or involuntary behaviour.
And most accidents have a sequence, or combination of failures.
Therefore, in almost all cases, there is a cause involved but we generally don't have enough investigative skills to find the intangible ones like fatigue, stress, work pressure. On the other hand, my observation over years of viewing the average investigation, is we don't have the skills to even find obvious physical causes either. Accident investigation is something of a hidden art, available to very few people.
We need to remember that the article was written by a journalist (no criticism intended Peter). The terms "human error" and in particular, "complacency" are appallingly archaic . Sounds the same as "Told him/her to be more careful in future". However, the paragraph that lists root causes sounds like a good investigation. There were also additional causes of lack of understanding and instruction, fatigue, dietary options (energy drinks) and the injured worker's arrogant attitude."
Leaving aside the vacuous statement about arrogant attitude, (they knew he had an attitude and let him continue to use a lathe, then when the poo hit the fan, they pulled it out of the drawer. I'd have kept quiet. That's having your cake and eating it too). None of the causes were, in fact, human ERROR. They appeared to be evidence of lack of knowledge, or human FACTORS, like stress and fatigue.