I would do the following:
1) Understand that there is either a miscommunication or a difference in values. Try to figure out what they are.
2) Next step is to make an attempt at building a bridge with the other individual.
3) If that doesn't work and if people are watching and listening, present arguments for the benefit of those people in a rational way and step aside once that's done.
4) If no one is watching and bridges can't be built, abandon the conversation immediately and move on.