Lucius Malfoy claimed to be Imperiused during his time as a Death Eater. That claim needs to have been credible enough that his allies in the Wizengamot could use it to justify voting not to send him to Azkaban. That doesn't mean it has to be very credible, of course. But it had better not have been common knowledge that Imperius only works on weaklings.
I think it was more that it works for nearly everyone, not only on weaklings.
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 114, and also, as a special case due to the exceptionally close posting times, chapter 115.
There is 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.)