they picked Western Pennsylvania as a socially conservative venue
As a resident of Western Pennsylvania, I will say that they knew what they were doing when they made that choice.
Didn't really matter, though. It seems that a jury never heard any of it. The legal wrangling before hand exhausted their ability to defend themselves at all.
Frankly, the whole thing's really repugnant. What they're doing is applying the community standards of one locality to something made elsewhere, solely on the basis that somebody there could order it if they so desired. It's not like California is foisting this up a bunch of Amish in Pennsylvania. California is making something available only to people who actually want to purchase it, and the people of Pennsylvania are prosecuting them because some of their citizens might actually want to buy it.
Alas, this is all a function of the Burger court. In the late 60's/early 70's they heard a plethora of obscenity cases, culminating in Miller. The upshot of it all was that the law can't prevent a person from possessing obscene material. The law can prevent it from being disseminated within a jurisdiction. The bummer part of that is that it includes mail order materials, so even though it's legal to possess porn in Bumfuck, it's not legal to obtain there. Compounding this is that the same standard was applied to the internet. The folks in Bumfuck can therefore prosecute the people who run an adult website, but not the person who downloaded the material.
The only saving grace is that each bit of material has to be deemed obscene, and rarely do communities care enough to actually take it to court to find out. Every day juries would be having to decide if Back Door Sluts 9 was obscene, even though 8 and 10 were already deemed acceptable. What has happened is that certain acts greatly increase the likelihood of getting that conviction, which created an enormous chilling effect in American pr0n.