

The person you replied to isn’t entirely wrong, though.
“ricing” was a term in use in the car modding scene around the 80s and 90s especially, where among certain groups it was popular to modify Japanese import cars with kits and decals etc to mimic the look of the Japanese racing scene.
Some people considered these mods to be tacky and worthless because they usually tended to focus more on aesthetics than performance, purely tricking the car up visually with no other changes. Due to the Asian origin of these mods and the stereotype that Asians eat a lot of rice, the cars were insultingly dubbed “rice burners” or " ricers" and the process of doing it “ricing”
It was intended 100% as an insult, basically meaning “Your car looks like shit because of all that Japanese crap you put on it”
https://en.m.wikipedia.org/wiki/Rice_burner
Like many insults of course, the insult is often “reclaimed” by the group it targets, who begin to use it between themselves in a favourable way, without any insult or negative connotation.
Ricing in the context of computers where people are styling, theming and “tricking out” their desktop almost certainly was borrowed from the car scene.
By this point there is basically no negative intent around the term at all, and especially not racist, but the place the term came from was.
YARE YARE