Honestly, if there was one point in history that marks when society started going the wrong direction, it was definitely 9/11. To some degree, it feels like it ties into a major problem humanity has in general; the attitude that "something must be done!" whenever a tragedy occurs. Everyone wants revenge after a major disaster or tragedy, or to inflict sweeping changes in the name of 'safety' that just remove whatever freedoms we once had.
That's exactly what the people who inflict these atrocities want. And if people could only understand that and act more rationally, things wouldn't be where they are now.