Professor Sinistra was talking about the unequal role of women in Muggle society, and brought up her mother as an example. "And that wasn't the worst of it," she continues. "Why, just a few centuries earlier -"
The writer cuts off at this point, but it seems entirely plausible that Sinestra went on to talk about how women like her mother were treated a few centuries earlier, and slavery is a pretty major component of that narrative.
If they were discussing "the matter of sex," then I agree it's a distraction from the discussion.
OTOH, if they were discussing how Muggle society treats its low-status members, with sex simply being an example of that, then it's a continuation of the discussion.
This sort of situation arises all the time in real-world conversations, where what one person considers a reasonable continuation of the conversation strikes another person as a confusing change of subject. All I can say is, it seems like a reasonable continuation to me.
I agree that discussing slavery would make perfect sense, given the conversation that preceded it. However, this ignores the conversation that followed it, whose participants seemed to be entirely unaware that they had been discussing any examples of discrimination other than on the basis of sex.
Based on Quirrell's remarks in particular, I'm pretty sure that they'd been discussing rape, in one context or another. As I said in my last comment, I'll provisionally accept that they were discussing it in the context of slavery, since I can't think of any bett...
Update: Discussion has moved on to a new thread.
The load more comments links are getting annoying (at least if you're not logged in), so it's time for a new Harry Potter and the Methods of Rationality discussion thread. We're also approaching the traditional 500-comment mark, but I think that hidden comments provide more appropriate joints to carve these threads at. So as of chapter 67, this is the place to share your thoughts about Eliezer Yudkowsky's Harry Potter fanfic.
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: one, two, three, four, five, six. The fanfiction.net author page is the central author-controlled HPMOR clearinghouse with links to the RSS feed, pdf version, TV Tropes pages, fan art, and more, and AdeleneDawner has kept an archive of Author's Notes.
As a reminder, it's often useful to start your comment by indicating which chapter you are commenting on.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: