The obvious reason folks oppose it is because the thought it may actually be a flag in the ground to the radical Islamic extremists who want all infidels (Non-Muslims; Jews, Christians, Atheists, etc) dead. And seeing Islam is almost 25% of the world population, it makes people wonder how many extremists there are?
Don't want to step on anyone's toes here--I know a Muslim guy who comes out to work and does intense mechanical work on huge printing machines. This Muslim also was a United States Marine for many years. I'm a Christian, he's a Muslim, and we get along just fine. Just wanted to clear that up for the politically correct people who are screaming at the top of their lungs right now, "RACIST BIGOT!"
P.S. It's a religion.
What ticks me off though is diners at a senior citizens center in Georgia can't publicly say grace over a federally-subsidized meal as the Left says that amounts to a government endorsement of religion. But the President can make a pronouncement defining Islamic theology at a Ramadan dinner in the White House, and that's not a government endorsement of religion?
And now the government seems to be embracing the mosque like it's the best thing since the idea of income taxes. It appears to me our government is embracing Islam too much while trying to shut down Christianity. I would prefer we all, Atheists, Muslims, Hindus, Christians, Jews, etc, were treated equally as Americans but apparently the Obamanation doesn't think so.