Raging against injustice, with guitars

“This machine here, it kills fascists too,” said Audioslave’s Tom Morello on Wednesday, pointing his acoustic guitar toward the capacity Troubadour crowd during a benefit concert titled “Axis of Justice.” The youthful audience cheered, though most probably didn’t get Morello’s reference to a slogan that once adorned folk singer Woody Guthrie’s instrument.

Morello (whose previous band was the agit-rock force Rage Against the Machine) and System of a Down’s Serj Tankian founded the nonprofit Axis of Justice to advocate such concerns as peace and human rights. Still, the three-hour show wasn’t exactly your mama’s protest music, what with Tankian’s frenetically freaky solo turn, and L.A. emo-core trio Apex Theory roaring out vague angst.

Then again, your mama wouldn’t have been totally alienated. Tankian, Morello, singer-guitarist Wayne Kramer, Red Hot Chili Peppers bassist Flea and System drummer John Dolmayan opened with the Bob Marley/Peter Tosh reggae anthem “Get Up Stand Up.” In a folksinger persona called the Nightwatchman, Morello performed resonant, unflinchingly angry and thoughtful originals, closing with Guthrie’s “This Land Is Your Land.”

Kramer eschewed volume for a kind of free-poetry with guitar, reflecting on the ubiquity of war with the chilling “Bomb Day in Paris.” And rapper Boots Riley of hip-hop act the Coup was compelling, even with only Morello’s guitar as backup. His words were as righteous as any MC5 lyric, from the sardonic fury of “5 Million Ways to Kill a C.E.O.” to the charming hard truths in a message to his daughter, “Wear Clean Draws.”

Fans actually listened throughout all of this talk set to music, and were rewarded with a cathartic System performance of complex, raging tunes. Indeed, if any fascists were in the room, they were surely vaporized on the spot.