Nobody is putting production databases in to commit history. At the size of twitch, there's also no way any application dev has access to production.
> credentials like a password for a database is (even more common).
??? What cowboy outfit is putting things which grant access to production customer data in to git?
And no, thats not a clever thing to do, neither is there a good reason to do it. But people do things you do not like and theres little you can do about it.
I would like to live in a world where you were right, but I am not. Sadly.
[Edit] dumps though are another thing. Not seen that, yet.
The site you linked to detects if the referrer url is HN and instead displays only an image saying "HACKER NEWS - A DDoS MADE OF FINANCE-OBSESSED MAN-CHILDREN AND BROGRAMMERS" instead of the content you are trying to link too.
wtf
A third reason would be finding a security flaw in the source code and exploiting it.