"The data involved consisted only of email addresses and information already visible on public SoundCloud profiles". So they've scraped public data. Why care?
I don't use SoundCloud, but if profiles didn't have contact information like Email Address on them then it could be meaningful to now connect those two dots.
Like, 'Hey look, Person A, who is known to use email address X, kept Lost Prophets as one of their liked artists even after 2013!'