I don't think its that people don't care about the flu. The flu happens. Nothing we can do about it, but our response to acts of terror is that they are unacceptable. Period. My grandparents generation dealt with the attack on Pearl Harbor. I would say that most of those individuals had a subtle distrust of the people from Japan after December 7, 1941. I once dated a girl from Japan. My grandmother loved her to pieces, but if you pressed her until the day she died she would tell you she distrusted the country of Japan. You might call that racist, but it wasnt really. She didnt have a racist bone in her body, but the attack on Pearl Harbor was so profound for people of that generation, that those scars ran deep.
Same with people I know who survived bombings in the UK. Many of them still distrust Germany.
Now both of those issues were perpetrated by the militaries of the goverments that existed at that time, and not by jihadists, or fundamental idiots. But they were so profound after the events took place the feelings were the same.
And in America, we had no one alive that had lived through any act of aggression against us on our soil (with the exception of a small island a few thousand miles away). So after 9/11 everything changed in America. Everything. Our terrorist radar is still extremely sensitive, and will be until the last person alive on 9/11 is dead and gone. Its our generational cross to bear, and I dont think we'll lay it down anytime soon.