yeah, they've been bad people for a long time:
""We're into the politics of people, we're not into politics. Like you talk about Northern Ireland, 'Sunday Bloody Sunday,' people sort of think, 'Oh, that time when 13 Catholics were shot by British soldiers'; that's not what the song is about. That's an incident, the most famous incident in Northern Ireland and it's the strongest way of saying, 'How long? How long do we have to put up with this?' I don't care who's who - Catholics, Protestants, whatever. You know people are dying every single day through bitterness and hate, and we're saying why? What's the point? And you can move that into places like El Salvador and other similar situations - people dying. Let's forget the politics, let's stop shooting each other and sit around the table and talk about it... There are a lot of bands taking sides saying politics is crap, etc. Well, so what! The real battle is people dying, that's the real battle." - drummer Larry Mullen in 1983.
when a band with that many fans is publically doing things, it makes a difference. They get climate change, it just might take them a while to figure out how to deal with it as U2: http://www.one.org/c/us/issue/10/