Take AI out…if a person can do it, which they can, the situation hasn’t changed. Further, it was a person who did it, with the assistance of AI. Also, the concept that you “can’t be exposed to the code before writing a compatible alternative” is utterly false in their arguments. In fact, one could take every single interface definition they have defined to communicate and use those interfaces directly to write their own, because in fact this i(programmatic) interface code is not covered by copyright (with an implicit fair use exemption due to the face the software cannot operate without activating said interfaces). The Java lawsuit set that as precedent with JDK. A person could have absolutely rewritten this software using the interfaces and their knowledge, which is perfectly legal if they don’t literally copy and re-word code. Now, if it IS simply re-worded copies of the same code and otherwise the entire project structure is basically the same, it’s a different story. That doesn’t sound like what happened.
Finally, how exactly do people think corporations rewrite portions of code that were contributed before re-licensing under a private license? It is ABSOLUTELY possible to rewrite code and relicense it.
Edit: Further, so these people think you contribute to a project, that project is beholden to your contribution permanently and it can never be excised? That seems like it would blatantly violate their original persons rights to exercise their own control of the code without those contributions, which is exactly the purpose of a rewrite.