I think this is related to the fact that you can push to GitHub as another user and make the commit appear as it is part of another repo.
After the youtube-dl event many people became aware of those "hacks" because someone used it to "upload youtube-dl into the DMCA's repo".
Since those hacks are known by GitHub but they won't fix it, someone thought that the best way to "protest" against the decition was to push GH's source into the DMCA's repo impersonating GH's CEO.
I don’t really consider non violent non cooperation as a sad form of protest over the iron grip corporations have over the proletariat. It is about all we can do. We can’t even democratically address the issue, we tried and the supreme court said nope.
Isnt this shooting the wrong man? IF you wanted to protest RIAA you would DOX lawyers, their families and friends. Hack and leak their private emails, dig up dirt like mistresses/embezzlement etc, not attack open source code repository RIAA happened to strong arm.
Github is complying with a mandatory legal process. It isn't like they are at fault here. As much as I hate what has happened, folks are attacking the wrong company.
Come out against the RIAA if you must do something. Better still to let the process work, you don't win legal battles by committing crimes.
An empire will always want to promulgate the idea that gerruila warfare is bad form, that the resistance should stand in an orderly lineup and fight fairly, may the side with superior resources triumph. Civil disobedience and conscientious objection are going to be more effective than merely communicating your displeasure to your Twitter followers or starting a petition on change.org.
It's unreasonable to expect that the individual who took this action could go to court against the RIAA and extract their deeply embedded claws from the legislative, executive, and even cultural environment in which they've entrenched themselves.
Instead, it's reasonable to expect that somewhere in a conference room at say, Gitlab, Sourceforge, etc., sometime in the near future, some lawyer is going to mention "We got DCMAs from X for repo Y, and foo for repo bar, and from the MPAA for the popular repo (insert software tool here), obviously we should remove all of those repos." Maybe someone familiar looks up and says "that sounds a little silly, isn't that tool just a general-purpose media player?" And the lawyer might respond "We don't care-we don't have the budget to determine if the DCMA notice looks valid or not, if it turns out to be valid we have to do it and if it's not valid it costs us nothing to take it down". Actions like this provides a reasonable response of "But, as we saw with GitHub, some of our users and maybe even some of our own employees will resent us for this. It could cost us users, cost us bad publicity, or cost us real money. Let's put a couple people on this for an hour or two to estimate the pros and cons."
Github was just a middleman, responding rationally to their existing financial, legal, and moral incentives, in a battle between their little users and the RIAA. Like a little flock of oxpecker birds riding a rhinoceros, we wouldn't even register in a fight against a tiger, we can only warn our larger intermediary of the danger we perceive. The RIAA doesn't care that you're against them. We need to change the incentives for companies like Github that have a chance to be heard.
Actually the takedown wasn't mandatory because (AFAIK, IANAL, etc) it wasn't actually a takedown request that GitHub received. Takedowns only apply to infringing content itself, not to tools. (Even if the tool were in violation of the DMCA it doesn't seem like the RIAA would have standing to pursue it.)
That being said, it also seems like GitHub is well within their rights to choose not to host a project accused of violating the law.
It's always good to remind oneself, that most dictators in history came to power through legal means. The Nazi's were democratically elected at first etc. Plus "Complying with a mandatory legal process" is a very relative thing for a multi-national giant corporation that pays very little taxes, hides most of its wealth offshore and is a leader in shaping the law through intensive lobbying.
Similar things happened with Sony over Other OS. Sadly I bet there will be further attacks and leaks as time goes on here.