"Catholicism was regarded by many people in this country as thoroughly incompatible with Americanism. "
except that Catholicism didn't represent both a religion and political ideology. if you look at areas where Muslims have become the majority they tend to push pressure on others to accede to Muslim demands. In France non-Muslim women were forced to wear the hijab so as to avoid harassment by Muslim men. in other countries merchants who sell items that Muslims believe are haram such as videos, music and liquor are regularly pressured to not sell such items.
or take a look at what takes place in Dearborn to Christians
the bottom line is lack of assimilation into a Western culture. Check out the problem of polygamy & forced marriages in UK