Attributing a pestilence or catastrophe of the day to a social group is one of the most common forms of bigotry, and a point of overlap between antisemitism and Islamophobia. Blaming Jews for the financial crisis is one example. Another is the leaflets accusing Muslims of crimes against humanity which were circulated in Preston, Lancashire.
Viewing phenomena through a prism is prejudiced, and most of us are prejudiced. Prejudice is a precondition for making sense of the world; if you don’t have a prism then you experience the world as an undifferentiated barrage of happenings between which you’re unable to prioritise. But if that prism is religion, ethnicity or nationality (not to mention sex, sexual orientation, age, and other immutable aspects of identity) it is bigoted. If you’re also looking for a group on which to lay the blame, you are looking for a scapegoat. None of these ways of thinking are against the law. The incitement to hatred kicks in if you publicly castigate your scapegoat and attempt to persuade others to see things your way. At that stage you have stepped outside the law.
None of this is obvious or to be taken for granted, as the thought-out incomprehension on Stormfront about the islamophobic heroin leaflets shows.