I edited this question's answer, but it was not bumped to the top of the front page like a normal post would.
I can only assume that down voted questions are not put at the top for some reason. So why is this?
The question currently has a score of -13, so its score is too low to be bumped to the front page:
Questions with sufficiently low score will not be bumped when either they or their answers are edited. The "sufficiently low" threshold is -4 on SO and new SE sites, and -8 on MetaSO (as of Aug 25, '10 -- see Grace Note's comment).
I'm not aware of an explanation on Meta.SE why this is, but presumably it is to avoid cluttering up the front page with low-quality questions.