Talking to another person, whether a new acquaintance or an old friend, is a fascinating experience; one finds points of view that one shares...and points of view that are quite different. At what point does one decide that the other point of view is a prejudice? I would decide that if I were to find, for example, that the point of view cannot be substantiated to my satisfaction. For example, if someone posts that usually, a flyover CAN ease congestion, and cites verifiable examples from other cities, I will modify my own point of view and say, in future, not that flyovers are useless, but that badly-designed flyovers are useless. But if I hear an opinion, (this is hypothetical) that Muslims are so dirty, with no facts behind that statement, I conclude that it is a prejudice I have come into contact with.
I find, too, that prejudices are SO hard to address. In the first place, the person is not even aware that s/he is prejudiced; in hes own mind, it is a reasonable, well-reasoned point of view. And if they are addressed, it is almost impossible to change someone's point of view on a preconceived notion. The only probability is that tempers will rise....!
Having said all that, I wonder how many prejudices *I* suffer from...and am not aware of!