A complicit media assures that the false flags are not pointed out to the general public. Without the MSM the false flaggers would largely be discredited along with those they are trying to elevate with these actions.
In occupied Europe the Nazis would regularly send out false messages pretending to be the Allies and telling to local population to rise up. When some did, the SS would be waiting to execute them.
It was a very effective tool for culling the population most likely to resist.