Instead of taking it down in the first place, Friedman should have told the RIAA to shove it, deliberately opening Github up to liability with the intent to defend this in courts and create precedent should the RIAA file suit. Even losing - and losing a few million in legal fees and damages in the process - and losing is far from certain - would create precedent that would create a lot more certainty of what goes and does not go with the current law, and give activists and lobbyists concrete jurisprudence to point to when approaching law makers and Library of Congress for changes.
Now that would have been real support. A somewhat risky move indeed, but also a necessary move if Friedman really thinks youtube-dl is an important piece of technology (with important policy implications).
Instead, he essentially left the developers, which lack the deep pockets of Github/Microsoft, to fight on their own, going even so far to suggest to budge to the RIAA's claims that youtube-dl contains a "circumvention" technology without challenge and remove the offending bits.
But at least he publicly stated he is "annoyed" by the RIAA. Talk is cheap. This is like showing up and telling David that "well, tough shit, Goliath is annoying but a lot bigger than you and will win, so you better capitulate, and I can help with that!".
(Yes, Microsoft being a RIAA member complicates things; Microsoft should in my humble opinion leave the RIAA; being a member of RIAA isn't compatible with their "we're the good guys now" image they are trying to foster regardless of the youtube-dl fiasco)