What it boils down to is that the Society refuses to accept what most other churches and schools learned generations ago...children have a limited attention span and cannot be expected to remain still and quiet the same as an adult...
What it really boils down to is that the GB finds children contemptible, a necessary evil to be tolerated, and would prefer that they act like mature adults all of the time.
Over the organization's history, most of the bigwigs / GB members never had children, and quite a few never even married. This led to a culture of utter disregard for the realities of childhood, which culture is now part of the deeply ingrained "spiritual heritage" that the organization is so proud of.