Not just debris, but the landing gear of one of the planes crashed down through the roof, destroying three floors.
But, no legitimate argument? The only argument against it is purely an emotional one that smacks of Islamophobia, which is about as illegitimate as you can get. If the YMCA wanted to turn the property into a community center with a 500-seat auditorium, a swimming pool, a restaurant, and a bookstore, that also included space for people to pray, no one would be freakin' out over it. But because the same exact type of facility is to be built by Muslims, we can't allow that? What's your definition of religious freedom? That's the litmus test.
Any argument that begins with something along the lines of, "Well, the YMCA didn't do this or that," fails, since Islam didn't do this or that, either. It was Muslim extremists that did it, not all Muslims and not all of Islam. Christian fundamentalists have done some despicable things, in recent times, so should we brand all Christians with the same iron? Unless it can be proven that this mosque and community center is strictly for Muslim extremists who would do us harm and not for anyone else, any singling out of Islam to disallow the mosque to be built near Ground Zero fails the First Amendment test.
The First Amendment, which applies to Congress and any local governments, states:
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
"Support the entire Constitution, not just the parts you like." - A Great American