This article explains that a dedicated effort by far right Israeli/Jewish extremists is pushing the anti-Islamic sentiment, in order to coopt Americans to their cause:
The Great Islamophobic Crusade
Nine years after 9/11, hysteria about Muslims in American life has gripped the country.
With it has gone an outburst of arson attacks on mosques, campaigns to stop their construction, and the branding of the Muslim-American community, overwhelmingly moderate, as a hotbed of potential terrorist recruits. The frenzy has raged from rural Tennessee to New York City, while in Oklahoma, voters even overwhelmingly approved a ballot measure banning the implementation of Sharia law in American courts (not that such a prospect existed). This campaign of Islamophobia wounded President Obama politically, as one out of five Americans have bought into a sustained chorus of false rumors about his secret Muslim faith. And it may have tainted views of Muslims in general; an August 2010 Pew Research Center poll revealed that, among Americans, the favorability rating of Muslims had dropped by 11 points since 2005.
Erupting so many years after the September 11th trauma, this spasm of anti-Muslim bigotry might seem oddly timed and unexpectedly spontaneous. But think again: it's the fruit of an organized, long-term campaign by a tight confederation of right-wing activists and operatives who first focused on Islamophobia soon after the September 11th attacks, but only attained critical mass during the Obama era. It was then that embittered conservative forces, voted out of power in 2008, sought with remarkable success to leverage cultural resentment into political and partisan gain.
This network is obsessively fixated on the supposed spread of Muslim influence in America. Its apparatus spans continents, extending from Tea Party activists here to the European far right. It brings together in common cause right-wing ultra-Zionists, Christian evangelicals, and racist British soccer hooligans. It reflects an aggressively pro-Israel sensibility, with its key figures venerating the Jewish state as a Middle Eastern Fort Apache on the front lines of the Global War on Terror and urging the U.S. and various European powers to emulate its heavy-handed methods.