If I didn't cook the rice, the rice would be called Mchele.
Unless of course someone else cooked it.
maybe they meant it as 'you didn't make rice', like 'you made something else instead of rice' type of thing
It's essentially the same as saying "You didn't make toast." If course, if no one toasted the specific bread, it's bread and not toast, but it's totally normal to say "You didn't make toast".
how am I supposed that it is you plural that is wanted here?
both singular and plural are accepted. The displayed answer above is only one of many answers accepted