And if GitHub required a person who posted code legitimately and was subject to vexatious interference from fake copyright claims to hire a lawyer, it would cost that person money.
Safe harbor doesn't give much guidance to hosting companies about who needs to hire the lawyer, other than to note that if they try to practice law by adjudicating these cases themselves, they're on the hook to hire the lawyer.
...and I think that if GitHub allowed them to post the content in the first place (ie it’s at the direction of the user, not GitHub’s moderators) and then when a red flag became known to them (for example via publicity) and they used common sense to ban that one repo, they would not lose their safe harbour they’d in fact be acting in accordance with it.
I had to fight off an obnoxious demand from an attorney representing a former employer so my first instinct was to reach out to the EFF. They couldn't help me directly but they maintain a national network of attorneys that are vetted and specialize in all things digital. It never came to actual courtroom litigation in my instance but we talked and she agreed to help me pro-bono (which was amazing to hear). I don't think I should get into more specifics but I will say the demand letter was so obviously bonkers she said she'd gladly slap down their lawyer and (if needed) represent me if they chose to take things further. Luckily simply calling their bluff was all it took and they backed off immediately. So maybe look to the EFF for a referral - It might not be free but if you need legal help as a code creator they may be able to offer guidance.
Safe harbor doesn't give much guidance to hosting companies about who needs to hire the lawyer, other than to note that if they try to practice law by adjudicating these cases themselves, they're on the hook to hire the lawyer.