Based on the question's wording, it hints that this is an opinion-based question and answer, but I don't feel that is giving Crane's text enough credit. Crane quite beautifully tells readers at the start of section 3 why the correspondent isn't so cynical as he normally would be. The whole first paragraph of this section is probably needed, but I'll provide the key bits of it below.
It would be difficult to describe the subtle brotherhood of men that was here established on the seas. No one said that it was so. No one mentioned it. But it dwelt in the boat, and each man felt it warm him. They were a captain, an oiler, a cook, and a correspondent, and they were friends, friends in a more curiously iron-bound degree than may be common . . . And after this devotion to the commander of the boat there was this comradeship that the correspondent, for instance, who had been taught to be cynical of men, knew even at the time was the best experience of his life.
The four men in the boat are in a harrowing and dangerous situation. Their very lives are at stake, and they know it. They know that they all have to put forth 100% effort if they want to have any chance of surviving nature's relentless and uncaring assault on their tiny boat. This team spirit, brotherhood, camaraderie, etc. is infectious and felt by all of the men. Even the correspondent feels this growing bond, and he loves it. The shared adrenaline over the danger creates a bond that he has never experienced before, and the associated euphoria is enough to overcome his historically cynical attitude toward other people.