What group or groups do you belong to? How does that set you apart or make you special?
Now ask yourself why you think that makes you better than people who are not part of those groups. No, don't get defensive - we all do it. We should at least try to be honest with ourselves. We all like to think that WE are better than THEM because we are set apart. The problem here goes two ways: First, it isn't true, and second, the OTHER groups think the same things about YOUR group.
Instead of excluding the OTHER, we need to treat everyone as part of US. Why? Because that's what Jesus commanded us to do.