https://www.gatestoneinstitute.org/20065/hamas-israel-inside-job
There have been two kinds of conspiracy theories circulated by ‘truthers’ after the Hamas massacre of Israelis.
The first kind essentially denies there was an attack or nitpicks the details. Those arguments are made in obvious bad faith by people who simply hate Israel and side with the terrorists. Any evidence presented to them is dismissed as fake.
The second kind of conspiracy theory is of the “inside job” variety most often involving a “stand down” order that allowed Hamas to massacre over 1,000 people without any military intervention. Some of the people pushing this stuff are the usual suspects, alt-righters and anti-semites, some of it’s coming from anti-war leftists and libertarians who treat every war as a vast conspiracy, and some from fringe figures in Israel.
The idea that Prime Minister Netanyahu or top generals would have issued a “stand down” (apart from being horrifying) makes no sense. Before this attack, he was the longest-serving prime minister in Israeli history. Now he’s been forced to join a unity government and polls show that most Israelis want him to resign. His political career may be over. Likewise that of the top generals. In Israel, they transition into politics. That is a whole lot less likely to happen now.
The 1973 Yom Kippur War disaster tanked Golda Meir and Moshe Dayan despite their heroic stature. There’s no political gain to letting the enemy murder over a thousand of your people in a preventable attack.
Finally, Israel is a small country. A whole lot of people know each other and are related or friends with each other. This conspiracy theory requires you to believe that military personnel who had friends and family living in these communities decided to ignore calls for help and sit around playing cards while they were being butchered. Not to mention ignore attacks on their own bases and allow their fellow military personnel to be murdered, tortured, and taken hostage.