I eat butter all the time, but gave up pork (and beef) 20 years ago. Pork, lard, bacon fat, etc., DO affect me. Badly. (Can't be far from a bathroom for a few hours after ingesting a very small amount.)

It DOES affect me, having been (to the best of my ability) beef- and pork-free for 20 years. Simply eating food that was cooked where pork was recently cooked causes me to have diarrhea for a few hours.

I have not intentionally eaten any pork products since 1989, and I can tell you that if I had eaten your bean dip with lard in it, I would have had a mildly upset stomach and diarrhea for the rest of the evening. (It's happened to me many times when I inadvertently end up eating a bite of vegetarian egg rolls that aren't, or hash browns that were cooked where some bacon was just cooked.) Maybe your friend didn't feel ill. Or maybe she didn't feel like announcing it to you or other guests at her party. But I wouldn't assume that she was OK.