Interesting points, everybody. 🙂 I like your point, my own kind of jew, about sentience. That could very well be the defining factor between Binky and Pal. Binky and HK are, in some way, persons (i.e. sentient beings), while Pal and Charmy Kitty are not.
My next theory is that these are futuristic, mutated beings from the future, descended from humans or perhaps the subject of genetic experiments, trying to imitate the relatively successful culture of the late 20th to early 21st century in hopes that their society will thrive better. 😛
Arthur and Hello Kitty are science fiction!