I love it when a new figurative sense of a word becomes so much more important than its original meaning that an unconscious pun becomes possible. Interestingly, to graze has also taken on a new sense and is still much on our lips¹ today, but still refers to feeding the body rather than the mind. Why did browsing, instead of grazing, come to mean looking through books and now webpages?²
¹ Yes yes, I know
² And why is it good to vet something, but bad to doctor it?