Lunch that day for me was a lesson in the ultimate form of respect. How often, when talking about someone, do you mention their race or weight or hair color or even gender when that information is actually irrelevant to the discussion. Welcome to subtle prejudice. Changing prejudice is neither fast nor easy. It requires sincerely questioning often closely held beliefs, attitudes and emotions.
Hate comes easy, tolerance comes hard.
If you would like to change your attitudes I would suggest, at least, the following steps. First, closely evaluate your belief systems and search out overt or covert prejudice. Then begin to take on tasks that might strongly challenge belief systems. As you do this evaluate what you will lose and what you will gain from changing the attitude. Frankly, if there is no gain, why switch.