The cross was not built for the site.
It was steel recovered from the site that broke into the shape of a cross. It is very appropriate for it to be placed there.
You better get a big box of explosives and be ready to destroy tens of thousands of memorials nation wide that have crosses on them or part of them if you wish to enforce that statement.
I can think of over 20 war memorials dating back to the Revolutionary War that are on government land within a 10 minute drive of where I sit. They all have crosses and other religious devices as part of them.
And get your facts right.
99% of the people opposed to the Ground Zero mosque said they had every right to build a mosque, but felt it was inappropriate. The other 1% are the usual nut jobs.
They were responding just as many Jews felt it was inappropriate for a group of Roman Catholic nuns to build a convent near Auschwitz. The nuns intended to pray for the souls of those who died there, but they agreed with the outcry and moved a few miles away.