I think it is fairly obviously this, quote from the article: the consumer sees a relatively unbroken field of red protein, creating the illusion that the bacon

I think it is fairly obviously this, quote from the article: the consumer sees a relatively unbroken field of red protein, creating the illusion that the bacon is leaner than it is. Fat is bad, so it's hidden. But fat tastes good, so if you look at the back window, you see it.