15.6 years doesn't seem like enough time
From a purely theory of punishment standpoint, these situations are truly fascinating. It's one of the few areas where most laws lump producers and consumers into the same basket while sentencing them (whereas, in contrast, most laws differentiate greatly in sentencing ranges between a person who sells or makes drugs and a person who merely uses drugs). The theory there is that CP (common acronym for child porn) is so uniquely awful that it's worth any deterrence, no matter how potentially "unfair" to the consumer, offenders can experience while considering making the stuff. I gotta admit when I have to view this evidence it's easily the most definitive proof that I have ever seen that God does not exist.
All that said, I'm still of the opinion that 15.6 is still overly harsh for simply possessing child porn.* I don't see a market causation argument since there is no "market" for this stuff, in a pure economic sense, as the pictures are usually shared in some peer to peer network. Arguably, the majority of the harm to the victim has already occurred and the odds of the victim coming to learn that the otherwise "normal" guy who has this disgusting fetish for this material that he leaves alone in the middle of the night in his home study viewed the material is pretty minimal (my understanding is that a lot of this stuff comes from overseas). Additionally, it seems counterintuitive to punish a cp consumer the same (or, in many case, worse) as somebody who actually committed these acts. Ignoring any 8th amendment arguments, it just seems like a bad idea from a policy standpoint because it creates no incentive for a person with these awful desires to view cp instead of seeking out his own victims and actually acting on his desires (the worse of the two evils).
*The most recently linked article alludes to Fogle also distributing cp. If that's the case then 15.6 seems right in the wheelhouse and, to me at least, appropriate since that furthers the harm to the victims. But my understanding is that he pled to possession only. Alas, this is why I always don't trust a media article on a court case but they so often get details wrong that, legally speaking, are hugely important.