smiley,
I totally get where you are coming from. It seemed like immediately after "9/11" every car suddenly had at least
2 bumper stickers declaring "I'm Proud to be American", etc. And every other house put out their American flag. (Some of these flags have been up since then & are fadded and/or torn & need replaced

but that's a separate issue).
I don't think people suddenly became more patriotic, I think the tragedies simply reminded them of the good things about America, too. And they wanted to show solidarity & pride in America.
To make another analogy: Greeks can be really into wearing their letters, putting stickers on their cars, etc. when they 1st initiate into a chapter. After a couple of years that enthusiam wears off some. But then maybe they get a little, who's very excited & they go through the whole process & it comes to initiation. All of a sudden that pride is renewed because they're sharing it with someone. It never went away, it just resurfaced.