Read it in the context. The “made up” wasn’t a general statement. No one argues stealing doesn’t exist at all. My friend’s bike was stolen. What’s made up is application of this word to situations that are incompatible with what stealing is supposed to mean.
Compare this to “the smell of soup and the sound of money” type “theft”.
"copying is not theft/ stealing a thing leaves one less left/ copying it makes one thing more/ that's what copying's for"