I'm not sure if you have ever been to lower Manhattan, but there's not really anyplace to store such volume of debris. And, the debris had to be removed to look for survivors/victims. Given the traffic on the island, it was apparently more logistically feasible to load the debris onto barges, and move it to the landfill in question.
Right, but they knew there were human remains in the wreckage. It could have been taken to PA or upstate NY or even NJ.
Bad call, but considering the situation, it is easy to see how it was made.