In that instance, I don't think people would be saying that all Trump supporters are murderers, nor would they be calling for the banning of supporting Trump or that all Trump supporters should be deported.
Furthermore, it's not the criticism of Islam that's a problem — Islam has plenty of issues. It's the suggestion that, because a minority of Muslims commit despicable acts in the name of Islam we should ban the entire religion, stop Muslims from entering the country and expel those who are already here. If one is proposing those sorts of solutions, they can hardly be surprised if people think they are racist.