I would argue it's irrelevant if they looked or didn't look at the code. As well as weather he was or wasn't familiar with it.
What matters is, that they feed to original code into a tool which they setup to make a copy of it. How that tool works doesn't really matter. Neither does it make a difference if you obfuscate that it's an copy.
If I blindfold myself when making copies of books with a book scanner + printer I'm still engaging in copyright infringement.
If AI is a tool, that should hold.
If it isn't "just" a tool, then it did engage in copyright infringement (as it created the new output side by side with the original) in the same way an employee might do so on command of their boss. Which still makes the boss/company liable for copyright infringement and in general just because you weren't the one who created an infringing product doesn't mean you aren't more or less as liable of distributing it, as if you had done so.
Well, no. They fed the spec (test cases, etc) into a tool which made a new program matching the spec. This is not a copy of the original code.
But also this feels like arguing over the color of the iceberg while the titanic sinks. If you have a tool that can make code to spec, what is the value in source code anymore? Even if your app is closed-source, you can just tell claude to write new code that does the same thing.
Copyright infringement is a thing humans do. It's not a human.
Just like how the photos taken by a monkey with a camera have no copyright. Human law binds humans.