By elephant in the room I mean exactly what you're saying in regards to people like Silverstein and his pals. Most normies don't talk about that stuff, they just post jet fuel can't melt steel beam memes and stuff.
Obviously most of us here understand that the attack on those buildings was to drum up support from Western people to attack and destabilize Middle Eastern nations, which then created a vacuum where terror cells could grow, and it also created resentment for Westerners amongst those cells. Then they push those people into the West and feed them anti-Western propaganda to create a conflict on our doorstep. If normies haven't figured that out yet then they probably never will.
Edit: Also a pretext for more mass surveillance, although that was one of the more obvious consequences.