Another retread of the misconceived "AI as collage machine" idea behind some the early lawsuits, i.e. training data goes in and something intelligible comes out, therefore the output is "made of" the input. Non sequitur.

The author glosses over the actual point of contention, saying "through some mechanical trickery it will blend then together with some randomness to create something that is a new song".

'Blending together' is not what's happening. The "mechanical trickery" is the transformative part.