It is only to your believe that (you quoted,"Regrettably, Islam as too often practiced is incompatible with such a harmonious compact. As an article of faith, Islam considers all non-Muslims, even the so-called people of the book, as infidels - people who are to be subjugated or cleansed from Allah's earth.")
what you termed as infidel must be buried away. Islam does not taught those Now it is clear how you became ex Islam. You interpreted Islam based on your own understanding and now that you are suggesting muslim in America to categorize themselves.
You should be one of the lucky person to live in America leaving your country and enjoying life there and i believe so do other immigrants be it muslim or non muslim. But deep in your heart, you still love your own country. I wonder, how would you react when one day, if the US army attack and killed your whatever relatives you still have back in your hometown in Iran.
Don't think that all Muslim behave as what you might have thought and there are American Muslim there in America and there should be he first to categorize under which group you might belong to in their country.