Pretty terrible analogy. I have no idea if pickles are vegan or not. I would assume they are but I'm not steeped in the vegan ethos and many things have surprised me in the past as being non-vegan.
Animal products are constantly snuck into processed, preserved and packaged foods. I'd find it funny, but wouldn't be surprised, to find that something derived from an animal found its way into a jar of pickles 'for flavor'.