A FPS, on the other hand, lends itself to predatory tactics... seeking your prey and killing them without being killed by their defensive tactics.
The only reason we see it as a hunt and kill experience is because we're pretending it is. For us, the toons are people, and we are "shooting" them with "guns".
For a mouse, the toons are just colorful moving things. This would be no different than the "find the lever, hit the lever, get the cheese" exercise, for which they evidently have no aversion. Although, I haven't seen one of those experiments with a moving lever, so maybe I'm wrong.