Is pork listed as an ingredient on the box/pouch? If it is, then I think it's reasonable to expect people to read that. Of course, I know people dont' read labels, but cat food, esp stuff like whiskas, contains all sorts in addition to the named meats. If it's not listed then I think you have a valid complaint about them containing pork.
I have no problem feeding pork to my boys - quite a few cat foods, inc bozita I think, contain pork - although I wouldn't feed too much of it.