Because it is a red herring. Of course we all know why there is anti-Muslim feeling. There is anti-black feeling, anti-Jewish feeling, anti-Hindu feeling, and anti-latino feeling, among others. Despite all the education, there is always an element of bigotry which surfaces when society comes under stress. The difference is that all these other anti- feelings are quickly brought under control and people don't act them out.
In the case of Muslims, the media and certain opportunistic elements have used the terrorism issue to stoke the bigotry and to channel people's xenophobia towards one group as an acceptable outlet.
Again, no one has any issue with combating criminals; it is the wholesale generalizations and stereotyping that we are talking about here.
Well, I don't want to compare it to accidents or diseases because they are a different category. But the situation with drug dealers who specifically terrorize entire neighborhoods into submission and who wield enormous influence over weak governments in developing countries, is an apt comparison.