It's always been possible to make political points via music, particularly but not exclusively via vocal music. It's been done with opera for hundreds of years, often forcefully. There's the clue. You can do it with stories and narratives about the lives of people. You don't need to patronise the audience with explicit political opinions, either in the music or between the pieces. In fact, as some posters have said here, you're severely at risk of alienating even the people who agree with you if you do that. I might want to hear about trade union rights, the Clearances, Thatcher's atrocities, abortion and the hunger strikers, even God, as folk music is about real people. But I don't want to be nursing my pint with the feeling that I'm being preached at or having my emotions tendentiously toyed with. There's a clear distinction. Some of my very favourite singers have occasionally had me indulging in involuntary buttock-clenching on occasion. To me, it's a mark overstepped.