What happens if you have a legitimate publication and link to a source that happens to also have illegal material ? This opens a can of worms.
"At the site's peak in mid-2009 it generated up to £50,000 ($78,500) per month in advertising revenue, and was more popular than Facebook"
Anyone who wants to claim there is something actually materially bad there needs to provide evidence that some harm was done to the economy -- show that the public lost-out. That would be really quite interesting, because economic research seems to have had difficulty doing that so far.
File locker sites are not targeted. They're outside Spain anyway. The target are clearly the forums where people posts links to file lockers.
Do you think nobody cares about incidental linking? Just wait and see. What will happen when this law starts being applied? Obvious first move for these forums owners will be putting the sites out or spanish jurisdiction. People will also start to use other less specific forums to post links.
This measure will be useless, but legal monstrosities like "indirect profit" and other vague provisions will still poison the legal system.
This is just a dirty hack to placate US gov.