Bad guys reveal other bad guys

In Sweden we currently have an interesting situation where a hacking group called "Hackare utan gränser" (should probably be "Hackers Without Borders" if translated) hacked one of those auction sites where you make the lowest unique bid to win. The site in question is called bideazy and according to the hacker group's announcement (forum posting and following discussion entirely in Swedish) their database is full of evidence of the bidding not having been done correctly and it seems to show that the site and company owner has won a large amount of all "auctions".

And they also made most of that data publicly available.

This brings many questions in my brain, including:

First of course the evident discussion if one crime (the hacking) can be justified to reveal another (the scam), but what I think is more important: isn't auction sites and especially the lowest-bid kinds more or less designed to open up for the sites to easily scam the users? It is very very hard for someone on the outside of it all to see if things are done the right way and that all rules are followed. Heck, even a little tweak here and there would make a huge impact for the site but won't be seen by the public.

I also find it a bit funny that in this case is they seem to have stored the scam data neat and properly in their data base which the hackers found, and I really can't figure out why. If they wanted a database to show as a front end if someone would ask and blame them for cheating, then this wouldn't be the one. And since they really seem to be cheaters, why would they need to store and keep track of all the cheats in a huge database?