You don't need a 12 month process with a legal department to not take code without giving credit. This is not untrodden ground.
> they mentioned the original project in the README
They thank them for their "generous insights". That's not the same thing. If I take chapters unmodified from Harry Potter and thank Rowling for her "generous insight", that's still not okay.
> Peerd is quite different from Spegel, it's not just a copy with a small patch.
Nobody said it was. It does, however, copy functions and other entire blocks of code with comments directly from Spegel without giving attribution. That is wrong. That is plagiarism.