Not just modern sexual attitudes, but specifically the sexual attitudes you see in the Harry Potter fanfiction community. And I'm sure it was meant to be jarring. Magical Britain's culture is subtly but deeply different from that of the muggle country that shares its borders; it would be profoundly weird if there were no surprises, no culture shock.

Let us recall that this story takes place in the 90s and that Tom Riddle attended Hogwarts in the 40s. I don't think that his views on sexual politics are entirely consistent with those of the present-day, so he may view "virgin" as meaning "not penetrated by a man".

Thank you for writing this series Jonah. I'm don't have the time now to think deeply about this topic, so I thought I'd add to the discussion by mentioning a few related interesting anecdotes.

I doubt what made the Polgar sisters great was innate intelligence.

Another interesting anecdote is von Neumann not (initially?) appreciating the importance of higher-level programming languages:

John von Neumann, when he first heard about FORTRAN in 1954, was unimpressed and asked "why would you want more than machine language?" One of von Neumann's students at Princeton recalled that graduate students were being used to hand assemble programs into binary for their early machine. This student took time out to build an assembler, but when von Neumann found out about it he was very angry, saying that it was a waste of a valuable scientific computing instrument to use it to do clerical work. http://worrydream.com/#!/dbx

EDIT: Apparently, von Neumann's attitude toward assembly was common among programmers of that era. http://worrydream.com/quotes/#richard-hamming-the-art-of-doing-science-and-engineering-2

No, I mean she had an intact hymen probably, but it's just the fact that "virgin = intact hymen" is a pretty silly notion to begin with. Especially since it outright says she'd been Baba Yaga's lover for some time already. Having sex pretty much means you're not a virgin any more. Kind of the point.

I'd bank on other spells; "meaningless" is a pretty strong dismissal, and I don't think it could apply to something that let you become a disembodied possessing spirit. The Pioneer horcrux might just be an evil surprise for another planet some day.

What's a full system of numerals? Even in Proto-Uralic, you could say ‘four and one’, and a human mind would understand that (whereas rabbits start getting confused, if I remember my appendix correctly). Conversely, in English, we don't have a word for 21; we just say ‘twenty and one’ (abbreviating the ‘and’ to a hyphen, while in French and German the ‘and’ remains).

So, like Olympics level athletics, where winning takes skills that are increasingly irrelevant to any other use of them?

One problem is that things like this tend to lead to affective death spirals. You start praising virtue X (which is a virtue because it leads to positive effect Y), then you start especially praising the extremely virtues practitioners willing to do X even when it doesn't lead to Y.

He also said that if someone guessed the entire plot, they'd "know" immediately. I don't think any reader has had a revelation like that yet (apart from the mystery reader who guessed it near the beginning).

Naturally, political systems which require no one to defect are unworkable. But what makes you think that defection is an insolvable problem in this particular system? Just like individual people can act jointly against aggressive criminals, individual states/provinces/communities can act jointly against aggressive regimes.