The first effect of fear is to sharpen our self-preservation and to enhance our awareness of danger. Those instincts are useful, but hyperbolic—they claim the unfamiliar is more dangerous than it is, and the familiar more benign than we should reasonably presume.
The second effect of fear is that we act, but the choice of action depends on whether we use our fear as an impetus or as a caution.
There are a lot of people consumed by their fear. It’s okay to be afraid, and it’s even okay to be overwhelmed by it. But it is not okay to use your fear to justify prejudice and xenophobia. And it really is not okay to deny your unthinking fearfulness and spin it as a virtue.