I am coming round to the position that racism (and for that you can also substitute pretty much any other prejudice) is the biggest problem we face today. For the clearest example you only need to look stateside, but intolerance of differences is at the root of pretty much everything that is bad in the world. Whether you dislike someone because they are a different colour, a different nationality, a different religion, a different gender, follow a different political ethos, have a different sexuality, are older, younger, richer, poorer - the reason behind it really doesn't matter.
It's hugely ironic that most people are tolerant of intolerance, by which they don't speak against it, and as such perpetuate the trend of enabling the 'secret racists' (not for one second suggesting that's you, BobbyD) to feel more justified in their thoughts and behaviour, and to be more open.
Most people see racism as the easiest to define, simply because the difference is right there in front of your eyes. But that explains why so many don't feel able to be open about their sexuality, and why conversations about politics and religion get so easily inflamed, so very quickly.
I don't know what the solution is, even if there is one, on the large scale. All I think we can do is to to make a decision to stop any conscious or unconscious bias whenever we see it, and hope that enough people change their personal habits to make a big enough difference for society.