If we assume he assumes Harry is Voldemort, which seems like a good assumption given his recent behavior, he would think Voldemort would see the symbolism in the price. And then... what? Is he taunting Voldemort? I mean sure he's angry, but taunting Voldemort doesn't seem wise.
First possibility that comes to mind is that it was a nicely salient price point that Lucius could be sure Voldemort wouldn't be willing to pay to get back a valued ally. After all, Voldemort implicitly said as much before, if Dumbledore's testimony about his reaction during the last war is to be trusted.
Lucius probably doesn't want to taunt Voldemort, but he does want to win, and by persisting when Harry made it clear where his interests lie, Lucius has already implicitly opposed himself to Voldemort in the current conflict. I can't think of any other price point that'd work better, either, now that the precedent's been set -- a little lower sends a message that Voldemort is less serious in his intentions than Dumbledore, a lot lower risks being paid in full, and higher makes Lucius look desperate.
Depending on how well known the ransom story is, he might also have been trying to score points off the other people in the room by drawing an implicit parallel to those events. Of course, by doing so and getting a different outcome, he's lost some of the moral high ground; I'm not sure how much, though, given how cold Harry was being and given the little stunt with Umbridge and the Dementor. Lucius is also probably updating his estimate for the Harrymort interpretation downward now (previously he had a hypothesis that matched all his data; now he has new data both for and against and should be very confused), but I'm not prepared to say what the consequences of that might be.
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: