According to the news report, people in the audience started throwing bread at the singer. "Harwell caused quite a stir during the band's performance, first yelling profanities at the crowd, then being subdued by a security guard and finally walking off the stage ahead of the encore."
I was not at the show, so I don't know how things really transpired. The point to take away from this, though, is that news of such incidents travel rapidly via social media. Yesterday it was a trending topic on Facebook. Suddenly a performance that might not have even been covered by local press is national news.
It is something to keep in the back of your mind every time you take the stage. Had Harwell kept his cool, it would probably have been a non-story or the headlines would have been "Band Remains Professional In Front Of Crowd Of Losers".
I had an incident with a client where a misunderstanding by a fan during a concert turned into a wildfire of negativity and misinformation on social media. Myself and the band worked our asses off for two days responding to every comment to explain what really happened. In the end, the people who started it all publicly apologized and said how bad they felt for misunderstanding.
Is it fair that an isolated incident can receive so much attention? No. But it is the reality. You need to be ready to deal with it.