As offensive as the outcome may be (in that the defendant will likely walk), this is how we should want our judiciary to work. The legislature passed laws prohibiting the creation or possession of child pornography, which left a gap (intentional/purposeful viewing). The judge's job is not to fill in that gap and fix the legislature's mistake (that would be legislating from the bench), but rather to faithfully apply the laws, as written. Now that this case has brought this issue to the public's attention, my guess is that the legislature will act pretty quickly to fill in the gap and make this conduct illegal.
We can argue about the merits of the decision (e.g., whether unknowingly-created cache files constitute "posession," but the judge's general approach (not legislating from the bench) seems sound.
1. The legislature should have fixed this already.
2. Those who make, sell and distribute child porn should be executed. Of course, with the proper legal authority.
BTW you ain’t my conscience.