UPDATE: Ohhhh! Katz = Cats. I totally missed it. Seriously, I did. So, not anti-Semitic (really), just completely unoriginal and unfunny. But that's nothing new for Marmaduke.
Someone today, who will not go named because she's applying for jobs and needs to preserve her reputation, told me that she likes the comic strip Marmaduke. Now, that's rather abhorrent on its own, as every Marmaduke strip boils down to "Marmaduke is a big dog. Sometimes, he interacts with his owners and guests in a creepy over-sexualized fashion."
But today's Marmaduke, while nodding in the direction of the form, takes the strip in a whole new (well, not whole new) direction -- anti-Semitism! It's not just that one could interpret Marmaduke's refusal to stop at Katz Deli as a boycott of Jews, so much as I can't think of any other way the caption makes any sense at all.
Of course, my friend didn't read Marmaduke today, so I'm sure this wasn't a commentary on her. But seriously -- what am I missing here? What is the punchline of this joke aside from "even Marmaduke wouldn't eat at a deli named Katz"?