I think as a species, we feel the need to mark and remember tragedies. Air India, Pearl Harbor, 9-11, the Tsunami, the 1918 Influenza, the Halifax explosion, Titanic, whatever... Its what people do. We mark tragedies, and we mark successes.
As far as "wallowing" in it, sure, at some point, you need to move on, its part of the grieving process.
I have a much larger problem with TV news making "shows" out of murder and bloodshed, like the Jon Benet Ramsey case, than I do about 9-11 memorial programs. "Nancy Grace" is nothing more than a "murder for titilation" show, it serves no real purpose other than to be voiristic, long after the "need to know" info has been reported.
9-11 memorial programs served a respectfull function of marking a tragic anniversary.
Can it get over the top? sure, at times, but thats a sign to read a book or take a walk, you dont have to watch CNN 24/7....
Just a few thoughts.