The idea of pork as a "white meat" was hammered into American's collective heads during the 80s and 90s when red meat was indicted by the health-food establishment for clogging our arteries. The Pork Board and its advertising agencies tried to dissociate the pig from the mammalian branch of the the tree of life and shove it over a few twigs to the fish and fowl end of things. White meat was (is still) in many minds "healthier" than red meat, so it was creative and effective marketing to claim that a red meat was actually white. The fact that CAFO raised pigs usually do have very light colored meat made it believable. Nevermind the side effects, or perhaps more accurately the concomitant traits, of growing a pig fast enough for its flesh to be light in color are blandness, coarse muscle fibers, and often dryness when cooked.
My pork isn't quite as dark as the beef I sell, but it is comparable to the hue one finds in ground beef in the supermarket. The two pounds in the photo above don't have identical amounts of fat. The pork on the left is a little fattier, which lightens the color some.
I associate the darker color with full flavor and healthy animals not pushed to grow at unnatural rates. In the ground meat the muscle fiber coarseness doesn't make much difference, but in the prime cuts like a chop or a steak, fine fibers make for a better over-all eating experience.
My beef comes from animals that are roughly 2 years old. Some hamburger is from cull cows that are even older than that. I'm curious to see how dark the pork from older pigs gets. Will it always be lighter than the beef, or will it be about the same as the beef? Beef from yearling cattle is much lighter than from older animals.