We each have prejudices we need to work on. However, sometimes half of the battle is becoming aware and conscious of our words and thinking about how those words affect people. Sometimes it's easier to make ourselves aware than it is to correct someone else.
It takes courage to speak out and correct those who do...but it's important. Sometimes a simple comment causes people to think about what they said and may change what they say in the future. A courageous action has ripple effects you may never know about.