One of the things I really like about music, obvious statements, is that it is such a versatile medium. Be it one of pure art, a method of story telling, or a way to express an opinion.
Music has been used as a way to express political and social views throughout the decades and regardless of country, border, or genre. The Beatles, Creedence Clearwater Revival, and The Clash, and a majority of the genre of punk music, are known for their politically-charged lyrics.
IMHO, one of the most prominent and outspoken bands of modern-day is Rage Against the Machine (RTAM or simply Rage). Rage formed in 1991 in Los Angeles, California and consisted of vocalist Zack de la Rocha, bassist Tim Commerford, guitarist Tom Morello, and drummer Brad Wilk. They melded heavy metal and rap music, punk rock and funk with anti-authoritarian and revolutionary lyrics.
Rage's songs contain very forward lyrics and seem to emphasis the message simply by their delivery and style. Heavy distortion, blatant obscenities, and forward lyrics.
Rage released their first album in 1992 which contained one of their most popular tracks, "Killing in the Name." The lyrics protest police brutality, inspired by the beating of Rodney King and the 1992 Los Angeles riots.
Sources:
Photo Credit: NME