Hà is only ten, and we're reading her story, in her words, so it's not surprising that the tone in this book is innocent. After all, though she's wise for her age, she's still just a kid. And what do kids do? They make assumptions. They see something once or twice, and figure this is the way things always are, and Hà's as guilty of this as any other ten-year-old in town.
For example, Hà watches some Western movies while living in the tent cities, so when she arrives in America and meets the man who sponsors her family, she assumes he is a real cowboy who rides horses and stuff, all because he has on a cowboy hat. She doesn't even think twice about it—this guy has horse wrangler written all over him. So one day while they are walking, Hà decides to get to the bottom of this horse business. She says:
Hee, hee, hee.
I go, go. (3.11.12)
But he doesn't own a horse. The hat doesn't make the man, so though he looks like the cowboys Hà saw in the Westerns, he just isn't one—but Hà, in her childish innocence, is kind of blown away by this discovery. This innocence comes through time and again, which is only appropriate given who we're following through the book.
The thing about innocence is that it's often quite opinionated—there's something about not knowing how much you don't know that really makes people confident in their assessments of things. And Hà is no exception. She has a lot of ideas about the world, and since we're reading what feels like her diary, we get front row seats to her thoughts on the world around her. So when her brother walks in, ranting about the war, Hà writes:
Since starting college,
he shows off even more
with tangled words. (1.13.7)
In other words, her assessment of her brother thinking about and talking passionately about the war is that he's just trying to show off, not, say, deeply concerned about the destruction of their home. An older and more mature person might come to a more nuanced conclusion, but Hà is confident in her opinion that her brother just likes the sound of her own voice, and her journal—which we're reading—is the perfect place to call 'em like she sees 'em.