I'd say its called creating an analogy where one shouldn't. As a general rule, and maybe I'm too influenced by Dijkstra -- don't introduce metaphors/analogies where you can reasonably talk w/o one. In this case, no clarity was introduced by its addition.

It's like adding gravy to mashed potatoes. Sure it may make the potatoes taste better, but now you can't put the gravy back in the gravy bowl, can you?