When worlds fail to achieve consensus

I'm of two, entirely contradictory minds when it comes to politics and everyday life.

Part of me believes that there is a time and place for such discussions, and that other spaces should be free of the noise. People sometimes talk about politics over the lunch table at the firehouse, and I seldom take part. In my job, we have to trust each other with our lives, and discovering that your colleague has world views you find ridiculous/incomprehensible/laughable/vile can only corrode that trust. 

On the other hand, I also believe that no aspect of our lives, public or private, is free of the profound effects of our social and political milieu. When we ignore that, or remain silent about our views, we tacitly endorse what is happening around us. We have a moral obligation to speak out about the issues we care about. 

Like most people, I walk a line between these mindsets. I pick my battles, speaking out about the stuff I feel I can't ignore, letting the rest pass by. To its credit, the fire service has by far the most diverse spectrum of political thought of anywhere I've worked. Diversity of opinion benefits a group, and might lead to better overall decision making, so the idea that the world would be right if everyone thought like I do is self-serving narcissism. It can be tough, on any specific occasion, to know - is now the time to speak my mind? Am I exhibiting weak moral fiber if I let it pass? Or am I indulging in pointless, divisive grandstanding by speaking out?