There's logic behind it.
Sifting throught it's R/S/E Pokedex entries here brings up that it is a gutsy Pokemon and will actually take on a Skarmory on equal footing. How would it take on a Skarmory? With its voice.
Taillow can learn plenty of moves that involve sound by plenty means. It learns Growl, Round, Echoed Voice, Sleep Talk, Snore and Boomburst, all moves that involve sound.
With it using its sound in combat, it only makes sense that it can use an attack that attacks with the destructive power of a terrible, explosive sound.