The problem here is not just that they are violating the GPL. The problem is that due to the GPL anyone who distributed or distributes one of the affected Emacs versions is violating the GPL.
Technically, it's only everyone but GNU that (re)distributes emacs with the generated code that violate GPL, so you are correct in not calling that particular part a problem.
Comments
The problem here is not just that they are violating the GPL. The problem is that due to the GPL anyone who distributed or distributes one of the affected Emacs versions is violating the GPL.
A simple README doesn't solve this issue.
Technically, it's only everyone but GNU that (re)distributes emacs with the generated code that violate GPL, so you are correct in not calling that particular part a problem.