My theory is that they wanted a republic because of what happened to the templars in France. They saw republics as being less risky for their goals. They kind of failed in England at first, but eventually succeeded when they got the bank and managed to keep Ann chronically poisoned and killed all her heirs before or shortly after birth.

They used that to install a foreign king / house that conspired with a bunch of masons, an organization that was dominated by jews, to setup a republic in North America. It didn't happen overnight, and not even under George I, but it was a long con and planned.