I think the conspiracy that the 9/11 were orchestrated by the US government are BS.
How could anyone in their right mind kill thousands of people just to get a justification to go into war?!
Well, I agree, although false-flag terrorism has happened before. Nazi Germany did it (as a pretext to invade Poland), the Imperial Japanese Army did it, and even Israel did it (... I think the government was behind the diplomatic bombings in Egypt, not entirely sure). Some historians think it dates back to the Roman Empire with the Great Fire of Rome, although that is continually disputable.
But yes, the actual 9/11 theory is bonkers, but I don't like how the term "false-flag terrorism" is associated with conspiracy theorists 98% of the time.