While reading stories such as The Crucible, that focus on the Salem witch trials, modern day readers tend to looks at civilians during that time as crazy. We think "who would ever accuse their neighbor of being a witch, so they would be hanged?". Thinking of something like this happening today seems unreal to us. But we can't be so sure that it has not.
For example, during 9/11, a lot of Americans stereotyped Middle-Eastern people as terrorists, just because of one group's actions. In WWII, Japanese Americans were put into concetration camps, just because of their race. Americans feared that they were harmful to the country, when they were just living their daily lives in America. This is extremely similar to what happened in Salem, MA. Innocent people were wrongly accused, and in turn their freedom and justice was sacrificed. In Salem, almost anyone, on any given day could be accused of doing witch craft.
If something like 9/11 happened now, concerning one specific group of people, the same type of situation could come about again on any race or religion of people.
These incidents did not happen too long ago. Who are we to say that something similar to the Salem witch trials will not happen again?