mtgox has enemies. They did a DDOS attack against them. They then moved to a hosting service that can deal with such attacks.
If you do a google search, you will see that a lot of sites that handle money has been ddosed, the common scenario is this:
1. Bad guy ddos target.
2. Bad guy sends a note to target asking for nnn dollars to make the attacks stop.
3. Target either pay or strengthen his setup.
This has been done against many bookies for instance in the past.
So in my mind, the attackers that attacked mt.gox is simply criminals looking for a profit, nothing else.
More reading: http://www.silicon.com/technology/networks/2004/02/24/denial-of-service-extortion-threat-for-online-bookies-39118605/
