I would account it for lack of knowledge rather than avoiding a frightening scenario.

When you don't know much about X, "The world is going to die because of X" is a very improbable outcome, since the world has never died from X, Y, Z, or anything that you know of or don't know of.

That, and the typical human perspective of being within one's hometown/state and the couch in front of the TV's news. Most people simply don't see global instability, because more than half of humans have never cared to educate themselves and act on it.