After reading the piece and seeing no explanation for why Farrell would be so angry, I found this quote from his wife about what happened:
"He felt that the stage volume had been extremely loud and his voice was being drowned out by the band," Etty wrote in her post. "Perry had been suffering from tinnitus and a sore throat every night. But when the audience in the first row, started complaining up to Perry cussing at him that the band was planning too loud and that they couldn’t hear him, Perry lost it."