During the piratebay case, the prosecutor only had to illustrate that it was likely (as in, convinced the judges) that copyright infringement had occurred. They did this by showing the top 100 torrents. They did not have to prove with certainty that the top 100 torrent actually was used by people. The fact that the names of movies and games showed up on the list was enough to convince the judges.
The lawyers defending the founders did try to make the argument that no infringement had been proven, and that the list itself was not proof of any infringement. It was just a list on a website, and they even presented evidence that the counter on the list was algorithm faulty. The judges was not convinced and applied the common sense approach that taken as a whole, it was not believable that no infringement had occurred by the website given the context of the site (the name, the top list, the overall perspective of how the site was designed).
