Hugh Hewitt opposes the mosque because he says:
I oppose it because the land and buildings damaged by the assault are now part of the sacred space of America's great civic religion. I would oppose the construction of any sectarian project there that wasn't a rebuild of an existing sectarian use for the same reason.
There is no formal designation for the sacred spaces of America's civic religion though they extend from the Mall to the Arizona Memorial. The land around Ground Zero is very much part of that space, and any project that politicizes it or brings a religious purpose to those sites should be refused.
The picture above is a sculpture by Fritz Koening, that once stood in the World Trade Center, and now damaged, sits as a "temporary" memorial to 9/11 in Battery Park. Battery Park's fences were damaged by patriots in the Revolutionary War, allegedly, because the tops of the fence posts had crowns on them.
Nearby, (unfortunately that photo "got away") is the Stock Exchange, and the place where Washington took the oath of office, as well as the church (Episcopal) Washington used to worship in; of course before the Revolution, it was Anglican, and the titular head of that church was George the III. And of course the Bull is nearby too; which was recently animated in "The Sorcerer's Apprentice."
All sacred space.
Just. Like. The Cordoba Center.