Dumbledore believes that Harry has just signaled to Lucius and the other Death Eaters that he will pay any price to save his friends.
Another way to interpret the events would be to say that Harry is willing to commit any act to save his friends as quickly and efficiently as possible. If Harry happens to have some money, he will use money. If he doesn't have any money, he may use some hitherto unknown, yet unimaginably horrific power, which is so destructive that it is capable of frightening a Dementor. I suspect that at least a few Death Eaters on the Wizengamot might be thinking along these lines.
Scaring the Dementor may have saved his bacon. Blackmailing someone is a positive utility move. Blackmailing someone who seriously believes they can destroy hundreds of unkillable soul-eating monsters, and backs that up is a move with totally unknown utility, possibly very, very negative.
The new discussion thread (part 15) 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 82. The previous thread passed 1000 comments as of the time of this writing, and so has long passed 500. Comment in the 13th thread until you read chapter 82.
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.
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: