How exactly could they “wreck” the servers?
The game servers are geographically distributed and independently operated. This group isn’t big enough, organized enough, or smart enough to launch a DDOS attack against even a noticeable percentage of the game servers.
I might be wrong, but I believe that the master server is handled by Valve/Steam. I’m 100% sure that Valve has faced threats from script kiddies in the past and are prepared to deal with anything that this group could throw at them. Valve also has massive bandwidth available that would make any DDOS attack against a Steam server virtually impossible.
They could flood the servers with trolls, but that would require every troll to first buy the game. Honestly, if they want to fork over $50 for the game and then spend a few hours trolling it I am 100% fine with that. It just means more money for SD.
The only possibility I can see would be an exploit in the game server code that they have somehow managed to find that would allow them to remotely shut down the game server, and again, I doubt they are smart enough to find something like that.
If they had access to the the database they might as well have had access to the salt, making the process of retrieving your password just a tiny step harder, if they used a salt.
Yes, well the point of the salt is to counteract rainbow tables and pretty much nothing else. The difference between brute forcing and doing a lookup against a rainbow table is a bit more than a “tiny step”.