That's not what I said. Anyway, I don't know where you are located, but at least in my country it is no problem to download the code from github for non-commercial educational study, especially given the listed facts. I think we can leave it at that.
Still not what I said. Let me be more precise. QSS management has clearly stated its intentions in its press release and actions (or inactions). And obviously, neither QSS nor its legal successor saw any need to take action against the referenced repository or the approximately 200 forks. Such action would very likely conflict with the current legal situation. Owners and users of the repositories could defend themselves based on fair use (educational purposes and based on QSS's own statements), implied License (also based on QSS's original statements), equitable estoppel (because of 16 years of toleration, and because of QSS's own statements, possibly a servitude created by estoppel), and even acquiescence (due to deliberate inaction). This has nothing to do with "the right to produce and distribute unlimited copies".
17 U.S.C. § 512(f) makes rights holders liable for knowingly false takedown notices. In the case of Online Policy Group v. Diebold, a court ruled that no reasonable copyright holder could believe the content constituted an "unlawful infringement" due to fair use. Diebold had to pay 125'000 USD in damages. In the case of QSS, a DMCA takedown after 16 years of tolerance with documented knowledge would be actionable as misrepresentation under § 512(f). A reasonable rights holder cannot claim that there has been an infringement if they have knowingly stood by and watched for 16 years.
None of the defenses you're citing here would hold water in court.
(We're not in court here, and there's nothing more to say, so this will be my last response about this.)