9/11 caused untold suffering and divided the world, but the internet was the line between the 80's world and the present.
I think cultural cycles really go roughly in double-decades. The early 60s look just like the 50s. The late 60s and 70s merge into each other. The 80s and 90s were another phase that petered out in the early 2000s. We're now in the post-2000 millennial era, so maybe another cultural phase is coming along soon.
(We had lots of terrorism way before 9/11.)
Then there was the torture and Guantanamo Bay Prison Camp, which is still open and housing prisoners. "We tortured some folks." War in Iraq (totally unrelated BTW), Abu Ghraib, countless civilian casualties, mass surveillance, militarization of police, it's really some horrific shit that came out of 9/11. News media lost a lot (all?) of their credibility during all this as well. For people coming of age after, all this is normal.
https://en.wikipedia.org/wiki/Patriot_Act
https://en.wikipedia.org/wiki/Abu_Ghraib_torture_and_prisone...
In my mind there was weird post Soviet innocence in the 90s where the West felt invincible and many believe Western style democracy would take over the world within decades. 9/11 was a rude awakening, and we have been living in its shadow for the last 20 years.
This viewpoint was well described (and I think influenced) by Fukuyama's book "The End of History and the Last Man"
https://en.wikipedia.org/wiki/The_End_of_History_and_the_Las...
No, general reaction was: The biggest military/nuclear power in the world is going to be very pissed, lets hope the results don't end up here.
And it did end up here. The US lost all moral high ground. All kinds of nasty military and spy industries smelled an opening, making the world a worse place.