I really appreciate this quest for the "lesson" it imparts: that there are some seriously evil people in the world, and in instances such as this when those people are doing evil things to other people, if you do nothing to stop the evil then you are simply condoning the evil that is causing others' suffering. Even if your reason is "moral pacifism"/"turning the other cheek", if you do nothing to stop evil when you see it, your pacifism is perpetuating continued suffering -- and that seems illogical, since most people choose pacifism in order to do the least harm. (There are, of course, other ways to go about "dealing with the evil" that aren't "killing the person doing it" -- but I imagine Mr. Sunflower assumes the Ascended aren't really interested in negotiating.)
Anyway, I think this is a great reminder for the real world.
Edit: Also, what [npc=225438] says if you speak with him after accepting this quest, describing the torture his superior subjects them to, then juxtaposing it by explaining that he "used to be my friend. He is still my friend, sometimes. Sometimes he talks to me like old times, and calls me Vi. Can someone be both things?" -- this really is fantastic writing. Vi'azl is presenting a question that would arise from someone with "black and white thinking": a mindset that everything is either one way or the other. It's something that I have struggled with my entire life. It's actually hard to acknowledge sometimes that yes, people are extremely complex and can be many things at once -- even many opposing, paradoxical things at once. And I feel that makes boundaries that much harder to set up and enforce -- if his superior were solely a torturer, it would be easy for him to hate him and want him dead. But he used to be his friend, and even still is sometimes...
I really love the complexity of the writing that Blizzard has introduced this expansion. It's so real, it's so relatable. This is the kind of writing I hope prevails in future expansions -- not to mention the normalization of mental health struggles and the treatment of them! +1 for that alone. :)