Somewhere in the Zendo I go to has been a notice that informed those in the sangha that we should welcome all without regard to race, gender, sexual orientation, etc. and to leave behind all "-isms": sexism, feminism, Communism, nationalism, etc.
I think that's a good practice for getting along with people. On the other hand, not all people will employ that stratagem, even Buddhists. Not even those keeping that practice of non-discrimination to all will keep that in mind all the time.
It is very difficult when I am the target of another's prejudices, especially when we all agree we're all progressive, good-hearted, good-natured people who understand that certain lines of thinking led to the Khmer Rouge and the Holocaust and what-not. One should not be silent, I think, because I think it's a delusion to think that somehow our mental processes are immune to those that captured those at the "Restoring America" rally. On the other hand, to be able to do this, while understanding and having compassion for the bigoted progressive lout ain't easy either. But it has to be tried. It has to be practiced.
In addition, it's important, at least for me, to constantly ask myself, "Is this true?" and not to actually hold to tight to - or even care too much about what I know is metaphysically certain.
I think that clinging too much to what we "know" is metaphysically certain gets us into trouble; or at least acting rigidly out of rigidly held beliefs hasn't always been good for me.