Well, what is he going to do with a magazine, anyway? Perhaps he was bored with his real chew toys. Or, maybe there was a devious-looking cat on one of the pages.
Dog: 1 Cat: 0
This is very likely only a meme created to be funny, and while the idea is a little bit morbid, it succeeds in getting laughs. This dog must have had some real beef with that alleged cat.