Japanese scientists conducted tests and saw that cats are more indifferent to the enemies of their owner.
Briefly about the experience of scientists writes Naked Science.They conducted an experiment in which the owners tried to open the box, and the cats watched them. At the same time, two strangers were sitting on either side of the owner. In the first part of the experiment, the stranger helped the owner of the cat with the box, and in the second he did not. Then both strangers offered a treat to the cat.
The cats didn't care if the stranger helped their owner or not.A similar experiment was carried out with dogs.They behaved differently in the same situation: they refused to accept food from a stranger who refused to help the owner.
It is assumed that cats simply cannot grasp such subtleties of social interaction between people. But this is not because they are "stupid."