Some prejudices are easy to debunk, based on irrationality. But sometimes prejudices are based on real-life experiences. Those types of prejudices are probably even more insidious.
We can make "pre-judgements" based on totally irrational ideas or totally rational facts. Sometimes we "pre-judge" for what we think are good reasons, for instance some concept of survival...
Still prejudice is wrong: morally and literally, and/or practically. To pre-judge a whole people based on some thing is so unimaginative!
Human beings are more than a particular group, race, religion, etc. To lump them into a category is anti-human. Not good for an individual or a society...
