Unfortunately, racism.
It’s a term from the car-modding scene. “Rice burner” was a pejorative term for badly-customized imported Japanese cars with more flashy looks than performance upgrades. It then came to just mean “heavily visually modified”, and installing such mods was called “ricing”
My Prusa i3 Mk3 treated me quite well - it wasn’t “out of the box” printing (even accounting for the fact that I got a kit version), but once I got it dialed in, I could just keep printing without having to fix things and retune.
Most definitely not “out of the box” is a Voron 2.4, which is my current printer. It was, however, so much fun to build and get running.