Quoting from wikipedia "For the simplest vehicles, the motion of the vehicle is directly controlled by some sensors (for example photo cells). Yet the resulting behaviour may appear complex or even intelligent."
One of the best nuclear astrophysicists I know thinks about stars as entities that want to stay alive -- "I'm running out of hydrogen, what can I burn next?" That approach yields the right phenomenology almost all the time.
Or do we simply fall into the trap the GP described, where once something is complex enough that we don't understand what is going on from a purely mechanical perspective we consider it close enough to human to empathize with it?
A much simpler question can be answered: is it possible to be cruel to an animal? The accepted answer revolves around whether or not you can influence the behavior of the animal (or machine). Crabs naturally hide under rocks. If you shock them when they hide under the rocks they eventually stop hiding under the rocks. Meanwhile a bacteria, by itself, will never learn to associate a stimulus with a condition.
That may capture the capability for thought. There are higher levels past it, like learning to model the behavior of other organisms, and those models eventually turning into a theory of self.