If you are not a copyright holder, then you are not in a position to make any demands. I find it especially ironic, considering when the GPL was actually violated on multiple occasions, even as recently as a few months ago, nobody ever takes issue with that.

Ironic that he says he understands licensing but doesn’t understand that, if you’re not a copyright holder, you don’t have standing to do anything about those violations. The Violations of GNU Licenses page states that if you see a violation, you should confirm the violation, collect as many details as you can, and then:

Once you have collected the details, you should send a precise report to the copyright holders of the packages that are being wrongly distributed. The GNU licenses are copyright licenses; free licenses in general are based on copyright. In most countries only the copyright holders are legally empowered to act against violations.

I remember reading about someone attempting to challenge that by suing for the rights that should have been conveyed to them by the infringer respecting copyright, but I wasn’t able to find anything on it. I did find references to people who were partial copyright holders being found to not have standing due to not having sufficient ownership to make a claim, though - see the outcome of https://sfconservancy.org/copyleft-compliance/vmware-lawsuit-faq.html