There's an argument to be made that a neural net learning from your proprietary "source available" code isn't violating copyright. It's not an opinion I would trust the judge to take over necessarily (they might, or not) and hinge my business on, but it's an opinion one can have, so I don't know that github violated any licenses here as afaik there weren't any at the time which specifically stated that <insert definition which can tell what-we-call-AI training and human training apart> is not permitted. At least not until you successfully sue them for it in some jurisdiction.