I really liked your recent drabble, but I don't see Mulciber calling Lily a mud-blood before she casts Snape off. I can see him talking about muggle borns in general and saying all kinds of things she calls him out on. And I can see Snape saying, "I don't want to hear it" or "He didn't mean it" but I can't ever see Snape telling Lily "It doesn't matter that he just called you a mud-blood. You're the one that's letting it bother you." Just no. :/ It comes down to how tactful Mulciber is or isn't.
Hey, thanks for liking it, babes.
I struggled a bit with figuring out Snape's response to it, because while I can personally see Mulciber calling her all sorts of things and giving zero fucks what anyone thinks, I was wondering how Snape would react to someone else--someone he considers a friend--saying it. I suppose more context on the state of their relationship could have helped! I see this taking place sometime in the second term of fifth year, and I hoped to convey that Snape knows it's a horrible thing to say, but that by now she shouldn't really be so bothered with Mulciber harassing her since it's not exactly new. So I saw it more as Snape being like, "It's MULCIBER being a prick as usual, don't let it bother you because this shit isn't new soooo." Obviously Snape doesn't quite get it, however. I guess I sorta based this off the fact that even friends can be ridiculously unhelpful even when they know how upsetting shit is. They think that their words are helpful when it is actually just offensive and offputting despite them meaning well.
I could see him sorta seeing how that retort could have come out badly, but the sentiment would still stand. I suppose the "it" in Snape's reply is moreso referring to the entire incident itself than just the word. He basically sees Lily learning not to get riled up over Mulciber's harassment as some sort of solution.
Woah this got really tl;dr but like any writer I have way too many thoughts even about the tiniest of things.
Oh and Mulciber is never v. tactful in my head, lol. Unless propriety dictates he has to be, he quite enjoys how blatantly offensive he can be, and I can see Snape being v. resigned to that sort of attitude to the point of inaction after a while.