If there was a grand secret society conspiracy pulling the strings in the world, they would love to have some definable group to put the blame it on. It is like the idea of the US -
being able to pull an operation like nine eleven and get away with it, if they had that sort of power they would not need to do the attack to begin with, and if they did not have that-
power, it would be wrong to assume that they would be able to pull it off. Incompetence and chaos is all that is needed to explain why US did not stop it, simplest explanation.