Considering:

1) Someone posted online to try to get hashes cracked and get passwords.
2) They originally offered the database for sale.
3) They could have spent a few days rummaging through accounts and quietly extracted bitcoins before serious red flags went up instead of doing a massive sell-off and only getting away with $1000.
4) After the sell off and market freeze they posted the database for all to see.

It was someone with purposeful malicious intent.

Someone sees as all as a bunch of suckers, and is just trying to cash out. That is all. Nothing else to see. Move along. No CIA or FBI master plan here. Just the usual business of people trying to screw other people over. Such is the way of the world.

Oh I assumed you meant malice beyond just self-interest.  Everything you posted fits the profile of an unsophisticated thief who didn't really know what he was doing.