Jim, I don't like seeing it as a paperweight on Rumsfeld's desk. In a museum or some other public memorial, yes. I don't see you or I dropping by Rummy's office.
For thousands of people, that is their grave. We never found most of the victims. To me every bit of the building, planes, etc. is sacred.
A lot of my attitude comes from a conversation I had one night with a veteran of WW2. I was participating in a "live aboard" program on the USS Lexington. He mentioned all the young men who had died on that ship and whose remains were either never found or buried at sea. Just like you wouldn't want someone spitting gum on your grave, the same holds for areas like this.
It's a matter of respect. Maybe I'm old school on this.