The documentary indicates it's unclear why he did it. It could have been to share, it could have been for his own research. His outlook on data was that it should be freely available to all but in the case the prosecutors assumed his motives. We don't actually know what he intended with the data. It's important to remember that. Because that small detail is enough to elevate the injustice of his death. He was destroyed for downloading too much information that should have been freely available in the first place.