Ishmael feels the need to explain Stubb’s behavior—eating a newly-slaughtered creature by the light of its own oil.
First, Ishmael lists several epicurean circles in which whale and porpoise meat are considered delicacies.
Next, Ishmael explains that the main reason whale-hunters tend not to eat the meat of their prey is that seeing such an enormous pile of meat as a whale carcass takes their appetite away.
Plus, whales are so rich—so oily—that it’s hard to eat much of them, although it can be tasty to dip bread in their spermaceti and fry it.
Ishmael speculates about the nature of eating meat. Slaughtering a whale might seem like murder, but slaughtering an ox probably did the first time it happened, too.
He suggests that everyone is a cannibal in some way; a cannibal tribesman who kills and preserves a missionary might not be as bad as the "civilized and enlightened gourmand" who tortures geese to get paté-de-foie-gras. We’re not sure we agree with this argument, but the production methods used to make foie gras arepretty disturbing.
Ishmael lists several other situations in which eating an animal is coupled with using something else made from its body—eating roast beef and using a knife with an ox-bone handle, and eating a goose and using a goose feather as a toothpick.