There's a growing band of pirates (the web kind) who hold sites to ransom via their massive botnets, in exchange for payment -- 'protection money'.
- Github are obviously very successful and may have money - their clients are reacting quickly on twitter so attackers might think they have an edge in terms of pressuring
Especially depending on the sum of money demanded, I can imagine it being cheaper to either spin up more servers to handle the load, or hire a DDoS specialist to help you out, or make it someone else's problem by moving behind a thirdparty CDN.
Your logic is sound - why trust a criminal?
But it's not like there's a better business bureau from organized crime.
The rich and weak Frank empire, a bad combination, resorted to the disastrous policy of bribing the invaders to leave. It only served to mark the Franks as a good target and emptying the treasury. The Vikings would leave, plunder some other place and come back for more.
In the end, the Franks ended up giving part of their land on the coast : Normandy. This served to settle the invaders down while making THEM have to protect their newly acquired territory against other vikings.
I'm sure it was tempting more than a few people with the resources.
Edit: just to be clear I meant any reader of signal vs. noise could have seen that (and Jesse's #1 comment and the jokes about DDOS in the comments) and decided to pull a prank. 37signals would never do that to anybody.