Earlier quoted context omitted.
Fuck the DMCA, not GitHub! AFAIK, they're legally required to take down material as soon as they receive a DMCA notice or else lose their safe harbor status. https://en.m.wikipedia.org/wiki/Notice_and_take_down
If you don't take down something you get a DMCA notice for, do you lose safe harbor status for everything, or just for that one thing? If the latter, then wouldn't it be a good move for GitHub to ignore DMCA requests that their lawyers are sure wouldn't hold water?
If you lose safe harbor status you become liable for infringing content on that service.
Infringement still has to happen and you'd still have to be taken to court and lose, but it's now "as if" you yourself uploaded everything.
So in this instance GitHub would be fine, but if they didn't take down the content then they themselves would become liable for any fringing content on their platform.
Or rather Microsoft would become liable, I suppose.
IANAL. That's just my rough understanding.
Fenwick and West has a lovely 36-page FAQ: https://assets.fenwick.com/legacy/FenwickDocuments/DMCA-QA.p...