This is something humans are, of course, largely blind to – though there are certain medications that can make you aware of it – but certain things about us are extremely freaky from the viewpoint of the animal kingdom. A human running or eating looks much like any other animal, but when they talk or do stuff with their hands, you really see the alien nature of the memetic parasite controlling them, I mean us.
It’s the same reason cats go for your hands when you try to type; nothing else in nature moves like that, and what it most resembles is arthropod movement.
Smol humans aren’t as purposeful but they’re still just really, like, busy. I was on a facetime call with my little niece and nephew earlier, where they were running around with the phone with me inside it, and I could really see how exhausting and stressful that could be for something like a cat.