The Wikipedia definition seems to indicate it has origins as a racist term and I’ve never understood why unix users have adopted this terms instead of something benign like “themes” or “theming” which I remember being in use long before I ever heard “rice”. So what gives? Why use “rice” instead of “theme”?
No, it originally was a derogatory term for people who modify japanese cars. Then it began to apply to shoddy or garish modifications to any car. Then people started using it to mean modifying something to their own tastes.