It absolutely was a false flag according to many structural engineers. The evidence points overwhelmingly to the conclusion that all three buildings were destroyed by controlled demolition.
"The total collapse of WTC 7 at 5:20 pm on 9/11, is remarkable because it exemplified all the signature features of an implosion: The building dropped in absolute free fall for the first 2.25 seconds of its descent over a distance of 32 meters or eight stories. Its transition from stasis to free fall was sudden, occurring in approximately one-half second. It fell symmetrically straight down. Its steel frame was almost entirely dismembered and deposited mostly inside the building's footprint, while most of its concrete was pulverized into tiny particles. Finally, the collapse was rapid, occurring in less than seven seconds. Given the nature of the collapse, any investigation adhering to the scientific method should have seriously considered the controlled demolition hypothesis, if not started with it. Instead, NIST (as well as the Federal Emergency Management Agency, which conducted a preliminary study prior to the NIST investigation) began with the predetermined conclusion that the collapse was caused by fires."