Here's why:
* Parallelism is the use of similar grammatical structures to express related ideas.
* The sentence uses the same structure for each phrase: "A hero embraces the truth, while a coward flees it, and a villain hides it."
* This parallel structure emphasizes the contrast between the actions of a hero, a coward, and a villain in relation to truth.
Let me know if you'd like to explore other rhetorical devices!