Uh, that's polyphonic music. There's plenty of classical music that isn't particularly polyphonic. Most of post-Baroque music is more homophonic: voices tend to move together in chords rather than independently. Counterpoint still appears but it's not the foundation.
also in this case he is not working with chords. they are just pitches moving.
I wish coders who are trying to do something in a creative domain would learn the basics and not just assume they can throw some simple algorithms at an artform and get anything close to an acceptable result.
No one is going to take a coder seriously if they can't code fizzbuzz.
Here's a thing to know: all the arts have their own equivalents. If you don't know what they are, learn them. Then maybe you can start thinking about non-toy algorithms and data structures that are going to impress an audience that cares more about quality of output than implementation details.
Most people who start working with domain-specific knowledge find it's much harder than they think.
That's the point I'm making. You'd get similar-sounding results by taking semi-random snippets of the source data and splicing them together with a tiny bit of glue logic.
The NN is more or less doing that anyway, but by more roundabout means.
It's a long way from there to being able to say that it has a non-trivial model of classical theory.