That is why some people are forbidden to contribute to projects if their eyes have read projects with incompatible licenses, in case people go to copyright court.
But even if that hadn't been the case, what exactly would be the problem? Are you saying that I cannot learn from a copyrighted book written by some respected and known author, and then apply that knowledge elsewhere because I would be risking to be sued for copyright infringement?
Which raises the question how many other important incorrect details are buried in the 13k lines of code that you are unaware of and unable to recognise the significance of? And how much mantainer time would you waste being dismissive of the issues?
People have taken the copyright header as indicative of wider problems in the code.
It's the same as if your colleague sitting next to you would not allow the MR to be merged for various political and not technical reasons - this is exactly what is happening here.
LGPL is a license for distribution, the copyright of the original authors is retained (unless signed away in a contribution agreement, usually to an organization).
"Are you saying that I cannot learn from a copyrighted book written by some respected and known author, and then apply that knowledge elsewhere because I would be risking to be sued for copyright infringement?"
This was not the case here, so not sure how that is related in any way?
Naturally there are very flexible ones, very draconian ones, and those in the middle.
Most people get away with them, because it isn't like everyone is taking others to copyright court sessions every single day, unless there are millions at play.