I am better able to understand what the 'divine simulacra' are implanting in my mind.
This made me wonder both what it is, and where it comes from in Epicurus' worldview. and then this next sentence:
The text in this chapter makes clear that our knowledge of Epicurean gods comes through prolepsis—a criterion of truth formed by repeated perceptions of divine simulacra striking our minds.
made me wonder if the author you reference, or Epicurus himself, defined a simulacra the same way as the following definition I quickly scooped from the Internet:
"Ancient Philosophy (Epicureanism): In Epicurean philosophy, "divine simulacra" (or eidola) were believed to be fine atomic emanations that constantly stream from the "quasi-bodies" of the gods and strike human perception. Perceiving these simulacra was a way for humans to form a concept (prolepsis) of the gods, who were seen as models of perfect happiness and imperturbability, but who did not actively intervene in human affairs.
Platonic Philosophy: The term "simulacrum" (from the Latin simulacrum, meaning "likeness, semblance") originates in Platonic philosophy, where it meant a copy of a copy of an ideal Form, often considered an inferior representation."
I left the Plato reference in there because it seemed to clarify the term a bit for me, but focusing on the definition from the Internet on Epicureanism, I'm wondering if his philosophy considers that the simulacra comes from the gods. And then if the gods are indeed influencing mankind's actions in a passive sort of way, isn't this opposite from being indifferent, as I thought Epicurus declared?