So, wealth, power, and this theme, hate, are all very much connected in this poem. (We're having kind of a hard time telling them apart, really. Bear with us.) They're tough to separate from each other mostly because they're all in a crazy, tangled relationship. In this poem, the wealth gives rise to the power, power usually causes one to accrue more wealth, and the combination of power and hate gives rise to the violence that is our first theme. At any rate, for reasons that are entirely irrational, Trujillo has decided that he hates Haitians. This isn't just him, either – historically, darker-skinned Haitians have met with an astonishing amount of prejudice from their lighter Dominican neighbors. It's a longstanding relationship founded and continued on hate. Trujillo is just an extreme example of an overall political climate. A climate, sadly, that's ended in the deaths of tens of thousands.
In "Parsley," the flames of Trujillo's racial hatred are fanned by the lack of control he has over his feelings about his mother's death – he conflates the two, even though they're not related.
In a perverse way, the parrot in "Parsley" becomes an object of Trujillo's hatred, receiving the sweets that the dictator despises.