I don't care that your offended that the mosque is being built. Nor should the government care that anyone is offended. What the government should care about is the legality of this mosque, and they aren't doing anything illegal. So thats that. They have the right to build there, and there isn't anything you can do about it legally.
Sure you can protest, and scream and yell, with this misguided sense that the "evil muslims are building a shrine to 9/11", but that's only going to make you look ignorant to everyone with common sense.