The young man was what [Daphne's] grandmother would have called a savage, too. But he hadn't been a savage. [Daphne] had watched him bury all those people in the sea. (3.67)
Daphne's grandmother: an elegant portrait of cultural insensitivity. Watching Mau early on helps remove the preconceived notions Daphne had, thanks to her grandmother, about his people being bloodthirsty savages. Whoa, they have feelings too!
[Mau] grabbed the stick and tried, as best he could, to draw a second skirt on the top half of the stick woman in front of him. (4.152)
While communicating with stick figures, Mau doesn't see any need for the girl figure to be wearing a top, since island women let the girls roam free. By glaring at Mau to change his stick-person drawing in the sand, Daphne is unconsciously trying to "civilize" him—to turn him from an "other" into something that she sees as civilized.
"[Trousermen] are so proud, they cover themselves in the sun. They really are very stupid, too." (4.178)
Trousermen are the Other to the islanders, and priest Ataba shows that ignorance works both ways. Calling them "stupid" isn't a good start to getting to understand one another.
[Daphne] had removed her dress and all but one of her petticoats. She was only three garments away from being totally naked! Well, four if you included the grass skirt." (6.170)
Remember: Daphne comes from a fairly uptight Victorian society. Clothes are a symbol of civilization. The fewer clothes you're wearing, the closer you are to savagery. (But three petticoats still seems like a long way to go.)
[The islands] are tiny and there's no one there. No one to speak of, anyway. (7.209)
What Mr. Red aboard the Cutty Wren means is that there's no one wearing pants on any of those islands. Pants are all that matters to these English folk. Pervs.
"It starts with knives and cooking pots, and suddenly we belong to the trousermen." (10.16)
Ataba is explaining to Mau how cultural assimilation starts off slow. At first, you're getting presents. Everyone loves presents! The next thing you know, you're wearing pants, and no one likes getting pants as a gift. Especially when you're forced to wear them every day. We have to say, Ataba might have a point, here.
"There are different ways to eat people." (10.22)
Ataba illustrates the difference between the cannibalistic Raiders and so-called civilized people: there isn't one. Each group makes others a part of themselves, and we're not sure which is ickier. (Well, actually, the cooking-and-eating one is. But still. The metaphor works: assimilation is another way of destroying people.)
"You shoot at people without a thought and you call them savages!" (11.108)
Daphne makes a good point to Foxlip, who practically views Mau's people as inhuman. Think about all the people who put Daphne in danger during the story. Were they islanders, or Europeans?
[The bullet] hit the water a few feet in front of [Mau], trailing bubbles—and stopped inches from his face. (13.19)
The final confrontation between Mau and First Mate Cox is the ultimate battle between "civilization" (guns) and "nature" (water). Guess what wins?
"No one is to take over anyone's country while we're gone, is that understood?" (15.80)
This is a funny line, but the fact that Daphne has to say this to her father's soldiers in the first place makes you realize how conquering new lands to them is as natural as changing their pants. You never can be too careful when Europeans arrive on your shores.
"Why is it always so, so... northern hemisphere?" said Daphne. "Turn the world upside down!" (15.128)
Daphne's trying to turn around her father's Eurocentric thinking. A lot of times we hear about the "Western world", but we rarely hear the world put into North and South terms (except for the American Civil War). Turns out, you learn some interesting things about the world when you do.