The thing that annoys me the most is when they start preaching their beliefs during their performances....If I wanted to be at a political rally I'd go to one, just shut the fuck up and do what I've paid to see you do.
The only exception would be Billy Bragg because that's his whole thing, and people know that when they buy the ticket.... well, it was before Wilco made him shite.
If someone wants to put it in their lyrics then that's entirely up to them, if you think they're talking a load of crap...like eminem, you just don't buy it. To dribble on about it during a concert is entirely different.