There was a time when explorers observed a primitive tribe exhibiting empathy or even morality might exert the same kind of hand-wringing as you did about whether it is actually so.
Same thing happened with chimps and the discovery of tool use. Jane Goodall was met by the same resistance. It is a characteristic, I would assume of the social organism as a whole. We have a lot in common with our little burrowing social friends. Empathy being one of them.
Altruism is also indicated by leaving the sweets for the trapped rat.
Im not a neuroscientist, but I can guess the mirror neurons are at play.
I think what they try to avoid is anthropomorphization. It's not a good idea to make assumptions that assume human-like characteristics -else we end up with cartoons.
It's not to say that animals are incapable, but such assumptions cannot be made without the insight being held suspect.
Much has advanced in science since. We now know the role of various hormones and chemicals that influence our emotions. Oxytocin, adrenaline, etc. The trick to get out of anthropomorphization is to avoid being human-centric when making the observations. i.e. put on an alien hat and observe human behavior the way we might observe animal behavior, and then based on that say that one acts in a similar way to the other, and reason they may have similar motivations.
