Legally, that's probably correct. And yet, it points out the absurdity of allowing melodies to be copyrighted in the first place. There just aren't that many of them, especially when one limits to the musically plausible set.

Melodies aren't copyrighted. Music publishing is complicated, but in essence song = non-trivial melody + lyrics.

"Non-trivial" doesn't have a formal definition, but it's guaranteed to be more complex than the 12^8 "melodies" generated here.

Actual plagiarism cases get much more complex, because lawyers will argue that specific features of the song, including the arrangement, combination of instruments, and so on, all contribute.

So the entire premise of this action is stupid. Nothing of value or interest has been copyrighted, and there is no chance the contents of that famous hard drive would stand up in a copyright claim against a commercial music release.

IMO this is basically a PR stunt.

Including lyrics in the definition of 'song' probably muddies the waters here, given the loose colloquial usage of the word 'song' appears to include instrumental compositions

The opposing argument would be that there are millions (billions?) of possible melodies, so selecting ones that are particularly pleasing is a significant creative act.

Picking out of millions/billions is way too little input to be a creative act. That would let you get a meaningful copyright on a sequence of two words.

There's probably a ML for that, or will be. Will it's output count as a significant creative act?

Is being pleasing a requirement of copyrighted material?

That is kind of the point. If the collection of melodies can’t be copyrighted then no one can be sued for infringing on them.

I believe that's part of what they're trying to point out. That melodies this short should be copyrightable by anyone.