Just because pigs are 'pasture raised' does not mean they are not fed grain. Did you ask specifically if the pigs were fed grain? I mean very specifically, as in verbatim asking the farmer "Do you feed your pigs grain, any grain at all?"
I work with a lot of farmers doing on-farm energy audits, and while many happily affix the 'pasture raised' label to their animals every farmer who raises pigs on a commercial scale that I've ever worked with supplements heavily with grain. Even for most pasture raised pigs, grain represents the majority of their diet, both in terms of calories and in terms of dry mass. Pork, among the various types of livestock, is the easiest to earn high profits for raising. Just do the bare minimum to earn some sort of premium label (like 'organic', or 'pasture raised', or 'humanely raised') and sell the meat, which will still be of low quality, at a premium price.
I often think of pigs as the carp of the mammalian world. Carp are regarded as a trash fish here in the US, mainly because they root around in the bottom of lakes and rivers, eat anything they find regardless of quality, and bioaccumulate all sorts of toxins. Pigs also root around in the ground, eat anything they find regardless of quality, and because their bodies have a high fat content I'd wager they also bioaccumulate all sorts of toxins.
Pig meat is not on my menu.