The 9/11 Memorial and Museum was intended to reflect and memorialize the profound impact that the 9/11 attacks had on all Americans and a call for peace, unity, and understanding. It was authorized by Congress and funded mostly by taxpayer dollars.
The 20-foot, 10-ton 'girder cross' that was found at the World Trade Center site (one of many, most of which were simply disposed of) installed in the 9/11 memorial betrays and belies this inclusivity. Despite its intent, the cross does not represent all Americans or even all victims of the WTC attacks. The girder cross is divisive because of its exclusivity of speaking only to and for Christians and therefore inappropriate to include in a memorial that is intended to represent and support all Americans.
The cross was preserved by a religious organization and worshipped as a religious symbol at the church site prior to its return to the 9/11 Memorial and Museum in July 2011. At the museum installation, an exclusive private religious ceremony was held to 'consecrate' the girder cross in the museum. This despite repeated calls and attempts by civil-rights organizations over the past 9 years objecting to this intent as offensive, exclusionary, and unconstitutional.