I don't think Russian courts care about slandering Japanese or American businesses doubt this lawsuit would go anywhere. I also doubt Gox would denial of service their competitors when they don't really have any on their level.
More likely some guy had his money seized by BTC-E for shady trading and reacted by slamming their servers and 'support' is just joking with the idiots in chat
Yeah that, it was very tongue in cheek from a non native English speaker. If you've been around and seen the user "support" 's mishandling of dialogue and sense of humor, you know it wasn't a real accusation, just a quip to say they're number two and getting more serious everyday.
Support had no idea who was DDOSing them when asked and assumed it was a random idiot like we all do.