> I don't believe this, and I doubt that the sense of copying in copyright law is so literal.

It is actually that literal, really.

> For instance, if I generated the exact text of a novel by looking for hash collisions,

This is a copyright violation because you're using the original to construct the copy. It's not a pure RNG.

> or by producing random strings of letters,

This wouldn't be a copyright violation, but nobody would believe you.

> or by hammering the middle button on my phone's autosuggestion keyboard, I would still have produced a copy and I would not be safe to distribute it.

This would probably be a copyright violation.

You probably think that this is hypothetical, but problems like this do actually go to court all the time, especially in the music industry, where people try to enforce copyright on melodies that have the informational uniqueness of an eight-word sentence.

> APIs are usually not copyrightable,

This was commonly believed among developers for a long time, but it turned out to not be true.

> This does not really sound like "the opposite of correct".

The important part is that information about the implementation can absolutely be in the spec without necessarily being copyrightable (and in real world clean room RE, you end up with a LOT of implementation details). You were saying the opposite, that it was a spec of the API as opposed to a spec of the implementation.