Replying to my own post here, but my initial post totally focused on the "are the contents of this guy's hard drive going to make him go out and abuse children?" question.
I totally ignored the question of the harm that the continued availability of this pictures might do to the victims in the pictures.
The ramifications of "revenge porn" are well known; it can be really hurtful to the victims for that stuff to be out there. It is, essentially, an ongoing sexual assault. (Jennifer Lawrence is one celebrity who has spoken about this at length) So, it was wrong for me to ignore that very important aspect.
Of course, it's not a given that this guy was distributing porn - there's a difference between saving a picture on your hard drive, and distributing it. If it was a torrent download, obviously, then he did both. And there might not even be people involved -- aren't underage hentai comics considered child porn in many jurisdictions? Barf, I don't want to think about this.
Because this is the internet and words get turned around so easily, let me be super clear that sexual contact with minors is wrong and I'd like to see it eradicated.
I have known victims of childhood sexual abuse. The lifelong damage caused can be absolutely devastating.