Is Poirot racist?

If not - and I think not - why is Charlie Chan?

Sure, Hercule is a mildly comic, neurotic, and obsessive character of dubious, if mostly nonexistent, sexuality, but he is always the smartest guy in the room, the English cop Japp is his foil, and Christie both mocks him with and uses him to mock British insularity.

And Chan?

Less the butt of the joke, but otherwise very similar.