At a conservative site I lurk at this came up and they too went on and on about the eviiils of Islam using the same language you refer to above. A fellow conservative pointed out to them the first amendment and the government cannot stop them from building the mosque the rest of them turned on him and reviled him for his lack of understanding the Constitution. If I recall correctly their arguments were one of either:
1. The bill of rights only restricts what the federal government can do. State and local government are ok to discriminate on the basis of religion.
2. Islam does not qualify as a religion
3. The Constitution is not a suicide pact and in times of war, like this, we can suspend certain parts of it.
The poor conservative who argued against these self-proclaimed "constitutionalists" was ridiculed roundly and accused of being a liberal.
ETA: I forgot to add that they all know that teh mosque will become a training ground for new terrorists. Seriously.
Which site is this?