So what? Is reading code the same as copying code or modifying existing code?

If you want to prove you did not make a derivative work, yes it helps if you never read the source code. Hence so call "clean room" implementations.

Why should I prove that? Let those who claim the violation prove that.

There is plenty of evidence already. The claim has been substantiated.

You can't just dismiss it then say the claimant has to provide proof.