I understand what you are saying, but I think they have been in this country for a long time without incident. They are managing to practice their religion without trying to change our government to an Islamic State. I do think their theology makes it difficult. I don't know any Muslims, so I don't know how much variance there is in that area of their theology. I've read claims that go both ways.
There are a lot of crazy religions, cults, and psycho beliefs all over the world. Mankind has believed in God in some fashion in every culture throughout history. It is innate to our nature. That doesn't mean all religions are equal and true because they are not. But that does mean that freedom for mankind cannot exist without freedom of religion. We might as well learn to live with the crazy ones while realizing the true author of freedom is God Himself. It is His right to judge them -- ours when they break our laws.
Regarding this article, and again without firsthand knowledge, many Muslims do seem overly hateful to those who disagree with them. I'm not comfortable with the statement that ALL Muslims are that way. I've met some that seem very meek and conservative and harmless.
Most religions worth anything believe theirs is the only way. I have no quarrel with that. So what. It's really about what attitudes and actions result from your beliefs. Killing = bad. Conversion by sword = bad. Conversion by persuasion = fine.
Islam is more of a political ideology than a religion...it cannot co-exist in a democracy as sharia supercedes any other law. Log onto Robert Spencer's, www.jihadwatch.org, or Daniel Pipes for specific references to this in the Koran and hadith...