Absolutely. As someone who fliered about Bush stolen election, most all African-Americans knew it. Supreme Court had to stop the vote count so little psychopath could win.
Kinda like how Hillary would've had to cheat massively to win, since no one liked her.
For 9/11 the Middle Eastern cab drivers all knew. And a few were good witnesses of the downtown area, but were reluctant to share.
They all knew. The people who were really actiivists? Demographically were young white males, very few woman - And many culturally conservative.
The African Americans may have known, but didn't become activists.
The lefties had no clue. We tried to figure that out - and the best reason we could think of, among many speculations "They believe America U.S. deserves it. And so it fulfills their expectations"
The young white males were all corralled over to "Alex Jones"
Also, If you talk to someone privately they would share their curiosity, but would be unwilling to do so in front of friends or family.
Many people with high positions in business or finance definitely knew - and some took their money and left the country in anticipation of what would come from it.
It's not really a secret to everyone.
One is to figure it out. Two is to care one way or the other.
One young girl commented "Even if 9/11 was faked, we'd still have to go kill them" That was something I would never expect anyone to say. The hate and ego will override thought.