Pig butchering is not just something that goes on in an abattoir, in many countries it's like a mini-festival. The idea is that in winter months each household butchers their pig, everyone turns up and gets fed. Then next week it's someone else's turn in the village to butcher their pig. Before refrigeration this was a great way to have meat regularly without needing to preserve all of it.

The image that this evokes in the minds of people that have experienced this is a big barbecue where various cuts of meat are feasted upon for a long time, maybe all day. It's a joyous event of unbridled gluttony. The guests must consume all of the un-preservable meat right away, which means if you attend one of these events you get to stuff your face with delicious, delicious pork for several meals, not just one.

To understand the origin of the "pig butchering" scam name, consider that most scams are one-offs. The scammer tricks the victim, the victim loses maybe a few thousand dollars, and learns "not to do that again". With pig butchering, the victim is tricked into feeding their money repeatedly into a fake "investment" application, which allows the scammer to "feast" on them for a long time, like at a pig butchering event.

Similarly, many long-cons take time to set up, but are still one-off thefts. That's not the same as convincing someone to repeatedly put thousands of dollars into the stealing machine.