Making fight decisions based on “could I kill it” is a convenience of human technology. The ability to seclude ourselves during healing and medicine allowing us to avoid infection, heal faster, and heal from more serious wounds has skewed how we think about fighting. Most animals make fight decisions less on “can I kill it” and more on “how badly can it injure me”.

Sure a human can kill a house cat, absent technology can the human do it without having the skin on an arm or leg shredded? Will the injuries be significant enough to make you unable to protect yourself from other predators? Will the injuries set up infection and kill you?

Cats are basically the perfect land predators. Even with their small size domestic cats are the most deadly and destructive hunters on earth.

https://www.scientificamerican.com/article/cats-kill-a-staggering-number-of-species-across-the-world/

They are ambush predators. They are really good at evaluating prey, identifying strengths and weaknesses, figuring out how, when, and if they should attack. Cats know whether or not they can win a fight. Cats will sometimes charge into fights they can’t win, like attacking the bear, because they know that they can inflict damage and that the other animal is making a similar fight decision. The hyper aggression of a 10lb claw tornado flying toward a 200lb bear is usually enough to convince the bear that the fight isn’t worth it.