That was my first thought. A “Tragedy” is an accidental type event.
A deliberate act such as 9.11 is MURDER, or an act of war. “Tragedy” is *NOT* a proper description of what happened that day. Anyone that refers to it in such a way is insulting each and every person that was harmed that day, along with their loved ones!
I think Jonestown was a tragedy of the first magnitude.