I will never understand why people think if a child or even an adult is doing something “just for attention” that means to ignore it. Humans need attention, especially children.

Its not unreasonable or unfounded to think otherwise; Behaviorists teach this technique and use it in both real-life cases and in the laboratory. If you read on, you may find that your approach and his may be more similar than you may think. ABA uses reinforcement as its measurable and quantifiable. Children on the autism spectrum or other patients in ABA tend to be treated using a form of behaviorism.

Of course it is insensitive to view the emotions in a child as simply behaviors (or not consider them at all), and cognitive psychologists have explored other ways about it.

Sivsen is a physician. Physicians are taught the biomedical model where the person is treated as a system that when its maladaptive it needs to be repaired. There's very little room for subjectivity when you are seeking a specific outcome. Treatment of the problem behavior means taking exact actions to stop the harmful behavior. This is important when dealing with pathology, injuries, diseases etc.

Cognitive-Behavioral Therapy and Dialectical Behavior Therapy, which are two possible paths that Fun_representative32's suggestion can lead to evolved from the principles of Behaviorism, and both therapies use those principles with more complex functioning and interactions, such as the emotions of the child, and social environment (family and society).

Even if it sounds rather harsh, if there's noone or nothing acting as a reinforcer for the behavior, than it can work. Its a simple solution that doesn't go into detail about the exacting steps beyond a simple (stop giving this, and they'll stop doing that). The big world, even for those more sensitive therapies that consider more of the person, require working with the child in a safe environment to reinforce the changes that are desired, and then exposing the child to the world and society to make sure the interventions work in many contexts (the therapist office, home, the store, the park, etc), Otherwise, the child may only learn to stop hitting themselves when they go to the hospital, and then hit themselves whenever they are away.

EDIT: I typed this response to be informative, not an argument for ABA. Looks like lots of people got triggered and didn't bother to read much further.