Maybe they did. Again, the quote is
[...] on the night Lord Voldemort tried to kill him, when Lily cast her own life between them as a shield, the Killing Curse rebounded upon Lord Voldemort, and a fragment of Voldemort's soul was blasted apart from the whole, and latched itself onto the only living soul left in that collapsed building.
If the only accidental Horcruxes made this way are similar to Harry, there wouldn't have been noticeable effects (assuming most people who aren't expecting it would cope significantly less well than Voldemort), and the shade left over would have passed on when the living Horcrux died. (The actual requisite for destroying Horcruxes is "damaged beyond magical repair".)
Or possibly there wouldn't have been a shade at all- maybe a mass murderer who didn't have a Horcrux to begin with would just die the same way everything else does when hit by an AK.
Or maybe nobody else in history had flayed his soul into ~3.125% of its original glory.
Yes, it's murder that rips the soul--but it's the process of creating a horcrux that takes half of what's left and seals it somewhere else. If you aren't making horcruxes, then you get a soul that's heavily damaged, but it isn't lacking pieces, it's just torn up. With Voldemort, you get a soul that barely has anything left and is constantly being torn up.
Even if you don't buy the death-mid-horcrux-ritual theory, does it make sense how damage that would normally be taken without notice could rip off whole sections of a soul with ~3% of the...size?...of the souls of even the worst non-horcrux-using mass murderer?
The next discussion thread is here.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 85. The previous thread has long passed 500 comments. Comment in the 15th thread until you read chapter 85.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
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: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15.
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: