I believe the point of the original comment is to make AI that comes up with its own original style, not one that "reinvents" an already existing style after first being trained on a different already existing style.
2) If we assume your premise is true. The public does not have a preconceived notion of what the art should be like. Presumably you would show them a style of art that they have never thought about before and they will respond positively to it.
Bach composed for the religious people, Mozart for nobility / people who could go to the opera, Beethoven for the romantic middle class who owned a piano, and Shostakovich for the oppressed masses in soviet Russia. The historical context shapes artistic criteria.
You can't make new art styles in a vat (brain in a vat), the process is connected to the world.