There's a lot of confusion here on what the term "false flag" means.

"False Flag" does not mean the incident is fake.

"False Flag" means that whoever did it made it look like somebody else did it. They used a "false flag" instead of their own flag.

The expression comes from the way pirates would sneak up on, say, a French cargo ship by flying the flag of France. The cargo ship thinks they're friendly and lets them get close. Then the pirates yank down their French flag, hoist the Jolly Roger, board the ship, steal everything, and kill everyone.

They used a "false flag" - one that was not their own - to sneak in and carry out a real crime.