I have not read all the posts yet, though I will comment strictly on how I believe this particular situation should be treated.
All people, which includes people of different religions, have the exact same rights as other people and religions in this country. This is the all based on the principles that the founding fathers of the United States laid out in the Bill of Rights under the First Amendment.
Though all religions are entitled to the same rights under the United States Government, does that give one religion the right to infringe on another to the extant that it causes a disagreement with the others religion?
Ethically, we are not allowed to judge another religion as all bad, unless all the people of this religion are such. Even if most of this religion is bad, how can we stop the minority of this religion from utilizing their freedom. Why would this minority want to force others into believing they are honoring our deceased if really they are all bad? I am sure there are those in their religion that are against the construction of the mosque too because they are against the honoring of our deceased. Even if this is not their intentions, we can not and should not judge them on the basis of the rest.
They have the same right as the rest of the religions in the world to build a place of worship.
We would not want others to discriminate against us, therefore we may not discriminate against others!
We are living in Galus and we do not have the right to run the world!