"I will not have a man on my boat," said Starbuck, "who does not fear a whale." (Chapter 26) Ishmael later declares that a comrade who does not have fear is more dangerous than a coward. The idea is that those who have no fear are prone to be reckless, endangering those around them. Sort of like the last verse of this song
I wrote a song nearly as bad as this in the 1960s, BTW, not intending any satire.
I am not any expert on courage and fear, so I offer not insights. What occurred to me was first Aristotle's doctrine that an appropriate fear was a good thing. He seemed to regard courage as a tool to be applied under wisdom. In Moby Dick, one would be crazy not to fear a whale, or to fear the dangers of the sea, or to fear what could happen under a captain gone mad. The doctrine of Just War in the Roman confession includes a reasonable expectation of success, or leaders are subjecting their poor soldiers to pointless death. On an individual or even small group level it may be different. Sacrifice in a (seemingly) hopeless cause may be more justified in such situations because it is an example, a demonstration, of what we cannot stop doing else we become lesser people. Again, I am no expert.
Yet this in turn reminded of one of CS Lewis's initial points in The Abolition of Man. He specifically countered the ideas in what he called "The Green Book" that to find a waterfall sublime is merely subjective, an unfortunate emotionalism that should be ruthlessly stamped out among English schoolchildren in the 1940s. Lewis found this deeply wrong. There are appropriate responses to many things, which can be called "merely subjective" only by torturing the meaning of the phrase. However much we burrow down and say that "beauty" is only a downstream effect of our preferring symmetry because it signified better health and better breeding potential, no one actually acts as if this is true. The men who say such things still have strong preferences, only somewhat malleable, of what "beauty" in a woman (or a building, or a song, or a pottery design is.
Fear of a whale when you are in a small whaling vessel with even smaller dinghies in order to land a harpoon in such a beast would seem to be an excellent example of why Lewis (and Aristotle, and Starbuck, and Ishmael) was right and the mid-20th C progressive idea was not only wrong, but rather stupid.