I can't be upset. My son suggested a similar idea about three months after 9/11 and I have marveled at its brilliance ever since then. His idea was even better than just a mosque and an office building, he wanted the world's leading Islamic study center to be in lower Manhattan.
Please think like a New Yorker for a moment. What is the best way to avoid another 9/11 attack on your city by Muslims? Answer: make Manhattan important to Muslims with a world renown study center and an important mosque.
Since the idea was first broached, I have come to realize that the U.S. needs to become the center of Islamic studies for Muslims. The reason is to support and empower the moderate Islamic world... which really exists. Lower Manhattan is a good place to start.