Cats have only been domesticated a few centuries as opposed to tens of millennia, and the Siamese was developed for use against humans; it's often more about capacity than desire. In fact, a neighbor of mine once had to give up a Siamese to be killed after it clawed another rather vindictive neighbor. Still, I'm reminded of that stat at the site I found warning us all of "the dog bite epidemic", that 77% of dog bites are from animals owned by friends or family: Even people who think dog bites are an "epidemic" don't think strays are the primary danger.