What aurum,mtgox and bitinstant did here is exactly the nature of bitcoin where a community should be able to work through arguments and evidence together
No. What they did is unprofessional, completely irresponsible (they didn't even contact the person they are claiming did something wrong--- so what is the point of the thread?), and possibly illegal.
That's possibly illegal, but I'll tell you a couple things which are REALLY illegal:
1- Stealing $500.000 between USD and BTC.
2- Unauthorized access to computer systems.
If the above 2 illegal matters aren't reason enough to fear repercussions from law enforcement because no reports were filed, why would Bitinstant, AurumXchange or MtGox fear repercussions for what they did in this thread?