As a sibling commenter noted, Islamophobia is probably the common word used in US media for this concept. Islamism, by contrast, is typically used in the English-speaking world to refer specifically to the ideological movements that hold that Islam should be the basis of political systems (that is, establishing explicitly Islamic states; implementing Sharia as the basis of state legal systems; etc). So anti-Islamism, then, would carry a different meaning than Islamophobia or anti-Islamic or anti-Arab sentiment more generally.