They mentioned the Marvin Gaye vs Robin Thicke case disparagingly. (I also think it was a terrible outcome.) But their project seems to support the idea that there is no objective measure of how similar two songs are. It follows that we should 1) eliminate music copyright altogether or 2) accept that human jurors will make decisions we disagree with. They might have been going for #1, but that is obviously way too idealistic to gain traction (in the USA at least).

I think that there can be a partially objective measure of song similarity, and that melody is an important component.