I think the word has evolved. Example. Back in the day, it was used towards a Japanese car, and/or the owner.
Now, it can be used for most cars. I've seen many riced out domestics or Euro cars. I think the word went more from a slang term for an origin of a car, to a term used to describe any car. Race Inspired Cosmetic Enhancements.
The word also gets misused by all the hillbilly and ********. If it doesn't have a pushrod boat anchor V6 or V8, it's rice. My DSM ges called rice, despite being virtually stock inside and out, and it's built in Illinois. The Hyundai, nobody really calls it rice. They just insist how unreliable it is. 181,000 original miles doesn't seem very unreliable to me.
The word doesn't bother me though. I drive the cars I drive because I like them. I can respect anything that was built well, no matter of the origin or the number of wheels or cylinders.