The reason the individual congregation corporations are shams is that the law says you can't have it both ways.
Either cong Elders are under the jurisdiction of the WBTS and must do what they say OR They are independant corporations.(kind of like a franchise)
The WBTS doesn't want to be legally or financially responsibile for the decisions the Elders make in their respective congregations. The WTBTS doesn't want to pay out any more money on lawsuits. In an attempt to accomplish this goal, they have set up countless corporations including making each cong its OWN corporation.
The problem is that IF the cong is legally and financially SEPARATE then they are entitled to make their OWN financial decisions.THEY NO LONGER ANSWER to the WTBTS. The society can't tell them who to hire and fire. (disfellowshipping those elders) They can't seize their paid for KH. They can't seize their bank accounts. Yet, this is exactly what happened at Menlo Park. They thus pierced their own corporate veil.
They want the "veil" of non-responsibility for lawsuits. They want to keep at arms length when it is in their financial interest to do so but at the same time they want to micromanage each one.