Is illegal where? Certainly not over here in Finland.
Chapter 28: Theft https://www.finlex.fi/en/laki/kaannokset/1889/en18890039_199...
Chapter 2, Section 12: Reproduction https://www.finlex.fi/en/laki/kaannokset/1961/en19610404.pdf
You are wrong regarding the copy of music being considered "stolen property" and your citation "Chapter 28: Theft" does not support your position. It lists many different types of theft NONE of the types of "theft" included there are in any way related to piracy or music.
You are right regarding that obtaining a copy of a song is apparently illegal.