You're talking about a mathematical approach to the choice of notes in a piece, while the article is talking about a mathematical approach to the choice of freq

You're talking about a mathematical approach to the choice of notes in a piece, while the article is talking about a mathematical approach to the choice of frequencies for the notes... which, as the article points out, relates directly to how the ear senses sound. Rather than leading to twelve-tone music, the article gives a physical reason why people might dislike twelve-tone music: it doesn't favor any particular frequency ratios.