I have to disagree. I see no bad taste in remembering what happened. In fact I find the ghost twin towers as a memorial to what happen on that day.

Now if they had the fire and smoke in them... that is a different story.
But just looking at ghost towers wouldn't cause the average viewer to feel the pain an suffering that happened on that day. But rather it causes the person to pause and remember.
Yes I am an American if you are wondering. Even though I personally did not loose someone, I totally understand that there are probably some people who will play this map, who lost a love one on 9/11.

But I think that they would appreciate knowing that we have not forgotten.
I REALLY LIKED erikkruchten's idea of putting op_air around the ghost towers. To keep them as a memorial, not just another part of the playing field.