The point is there have always been wardec immune people in EVE. And as long as there have been useful structures have been wardec immune people using that structure.
Your idea is not about closing any exploit, it’s about opening up more targets to you, right after CCP clearly said they want people to choose their element of risk separately from their social elements.
If someone wardec immune annoys you gank them and blow up any structure their Corp or alliance goes near, pretty simple. The more that hide in the immune Corp the fewer defenders you have to deal with.