I wanted to pass on an anecdote from a few years ago: My kids attend a local Jewish kindergarten. One day I walked into the littlest kids' room and saw that the kids were learning about farm animals. Someone had taken a piece of blank paper and pasted over the picture of the pig; however all other animals in the display were quite visible.
I was quite angry over this, because I do not believe in hiding my children in a corner of the world and pretending that non-kosher animals don't exist. I spoke to the teachers and said that I would only accept their covering up the pig if they also covered up the picture of the horse and the sheep-dog too, as they are equally unkosher. The next day I came in to find the picture of the pig uncovered. I was quite relieved!
You're right that the other animals are equally unkosher. There are even things "more" unkosher than the pig, such as insects (chocolate covered ants, anyone?).
On the other hand, the pig is seen as the most "insidious" of the unkosher animals, as it is the only animal known which has a true split hoof like a kosher animal, but does not chew its cud. In this, our Sages saw it as the "worst" of the unkosher, as it "puts on an outer show" of being kosher (split hooves), yet on the inside (chewing its cud, which is a function of digestion) it is "treif!" Thus, it symbolizes falsehood, the antithesis of Judaism.
