Let me be controversial for a moment...
One group of people fervently holds beliefs that dismiss any other group's fundamental tenets therefore this group is deemed as a threat to the latter's survival--physical or cultural. Really, isn't this the true reason for opposing the expression and practice of other religions? It's the fear that their values are so different than the prevailing ones and that those values will dilute or poison the good established socio-political culture.
How about the various laws against proselytizing? How could a religion tell the infidels about a good thing they're missing out if prevented from preaching openly and acquiring new members? [definition: proselytize] It's the dominant religion that uses the state to safeguard its own faithful from competition. The Founders understood this danger when they established the principle of separation of church-state. The courts have also ruled on the Establishment Clause.
I do believe in the First Amendment. Freedom of religion is part of it, as freedom of expression is too. Free speech means that people can argue about ideas, or just pronounce their beliefs without offering any proof. But, they can't prevent others from doing so. Here's a fundamental point: Respect for the right to free speech but no idea or belief system should claim immunity from criticism or evaluation. This concept is hard for many to accept. If I haven't examined my own ideology, my own cultural directives, how could I be "open to a dialogue" when confronted by people with different claims?
If I happen to be a tolerant person, I could accept others' religion to exist on the principle of tolerance but without evaluating their claims--unless I say, I know they're going to hell but that is their choice, those fools.... All major faiths claim the only true path to salvation while condemning others. And, here's the crux of the matter: Faith isn't up to rational thinking and critical evaluation whereas revision is possible or desirable. The dogmatic approach demands devotion, acceptance, and that a few special persons understood God's absolute commandments.
The Muslim organization that wants to build its cultural center, including a mosque, near the WTC has the legal right to do so and if this offends other people and organized religions so be it. Can you imagine how different our country would be if we made "being offended" a legal principle? Anything you do or say can be found offensive by a number of people. There would be no wealth of art, literature, music, fashion, etc. Granted, not everything out there is fine by me. I found many things offensive. What I don't like, I boycott not try to ban it legally. Of course, I'm talking about adults who have choice, not children.
Personally (adding to being controversial) I believe that all religions are fundamentally wrong. They pronounce edicts, deliver judgments, and construct arguments on the idea they have captured the only absolute truth--and only them can possess it. All major faiths (at least) are misogynistic. Their holy books contain passages supporting slavery, killing of the apostates and members of other faiths, promote blind obedience, superstition, and ignorance.
Humans have established more civil societies because they created the secular state and chose not to strictly obey the commandments in their holy books. I do prefer a more thought-out, rational, appropriate for our enlightenment-era society. Can you imagine the world whereas we killed adulterers, those who left a faith, those who worked on the Sabbath or wore the wrong clothes, ate the wrong foods or broke their fast, that we could beat our slaves, murder children for the sins of their fathers, commanded women to be man's property while we cut their clitoris once they became teenagers, etc, etc,...