Whaling is a hard trade. The massive brutes are elusive and men can spend weeks at sea without ever seeing one. Being simple folk, they tend to spend the time looking for reason in every slightest thing. Gnomes, for example, have been proven to be the cause for any and all calamities at sea, and so, goes the reasoning, it is better to destroy a gnome at sea than wait for destruction to come.
Unfair? Maybe. But it passes the time.