Considering that Israel pulled its citizens and troops out of Gaza in 2005 in the hopes of peace, I'd say not only is this an insane conspiracy theory but also just obviously dumb.
It may be false, but I don't see why would it be "obviously dumb". 2005 was nine years and a few governments ago; enough time for policies to change. After all, just eight years before that, the current PM, who was also the PM back then, presented a plan that included annexation of most settlements.
I'm not saying the theory is correct, again, I have no idea, but that argument seems weak.
Given that in times of war, truth is the first victim, the likelihood that black flag operatives are planted throughout the Gaza region is pretty high. There haven't been rational investigations into the Israeli claims that these rockets are fired by Hamas - the bullhorn is loud enough that people cannot believe anything else, because they don't hear it.
But Israel, of all states, is more than capable of pulling off these kinds of activities, and its been in the dirty-tricks playbook for decades (along with those of most modern governments with an Intelligence budget, to be fair).
Until we, the people - the true masses - demand a truthful process in place of propaganda and deceit, we will never know the real truth. The likelihood that these events are orchestrated by those who truly stand to profit from both sides is pretty high. There may well be a hidden third party between Palestine and Israel, intent on continuing to profit from the conflict, and those people - well funded, I might add - are very far from the visible center stage, nay the prison dock, where they belong.