A few quick thoughts.
1 - If you are reading a news article about something someone has said or done, and you find yourself saying, "I don't understand why...", frequently you should stop right there. That is a pause-and-reflect moment, or possibly a red flag that you're about to say something insensitive or even downright stupid. An extreme example of this is a comment that I remember a man making about poor little Megan Meier: "If being on MySpace was upsetting her, I don't understand why she didn't just log off and stay off." Well, because she was a thirteen-year-old girl, not a grown man. She probably wouldn't have understood why the commenter doesn't dot his i's with little hearts and wear pink underwear, so they're even. Which leads me to...
2 - ...People are different from each other. And that's cool. That's the real message of diversity: Don't expect other people to be like you. Don't wonder why they don't act as you do. And for pete's sake, where other people's actions and attitudes deviate from yours, don't consider this to be an area where they are flawed. It may be - if they deviate from you in that they lie where you are honest, etc., - but it isn't a foregone conclusion in every case. When I was at Pittcon I attended a little talk sponsored by Lab Manager Magazine. The speaker talked about personality types - DISC: Dominating, Influencing, Steady, Conscientious - and how people who fall into these catagories act, and how to deal with them. He made a point of saying that we all are any of these at different times, and that one is not better than another. Well, one may be better for a specific job function. But one is not morally superior to another, or more worthy of a human. I've been through a little bit of personality testing, and I think it's been worthwhile to get some insight into how I tick (e.g., why I get angry when the reason is not immediately obvious) as well as how other people might differ and how they need to be interacted with, which may be different from they way I would interact with them if I don't put some thought to it.
3 - Finally, if a person who is a member of a group of which you are not a member, talks about a problem of that group - racism, sexism, etc. - you don't have to accept everything they say without critical thought at all, but your first reaction should probably be to remind yourself that they are more likely to know what they are talking about than you are. You might ask yourself: if this is a legitimate problem, would it be a problem for me? And if the answer is "no" then be a little slow to dismiss their concern. Even if you think they have totally misunderstood the situation and the problem simply isn't there, if you start with "I can see that this looks really bad. If I were you I wouldn't like it either," you'll get a more positive response than "Oh, you're just seeing something that's not there. Quit looking for ways to get offended."