What may move us to defend something which we consider to be wrong?
This question might be responded in different ways, because the same words expressed as questions in different matrixes are indeed different questions.
Plato takes up this issue, for example in his 1st book of the Republic. A discussion about what is justice starts in this dialogue. The context is the celebration in Athens of the recognition of the Thracians as allies against the Sicilians. The Thracians had been enslaved for generations by the Athenians. As a collateral result of this new recognition, a part of the Thracian army committed a cruel massacre against the people of Mycalessus in the name of their alliance with Athens. As a result of this, they were despised by most people in the region.
Socrates proves that all the arguments to defend this massacre as just are fallacious. Thrasymachus, a Thracian diplomat on mission in Athens, is enraged by this, and he accuses Socrates of not taking into account the fact that crimes are only criticized when small. Successful genocides and enslavement of whole populations (as the Athenians committed), on the contrary, where considered "just" even by the victims. Socrates dismisses also that argument, but he concludes this dialogue by stating that despite all their reflections, they still do not know what "justice" would be – because Thrasymachus' point had no answer.
The idea behind this is that it is important to dismiss arguments as fallacious. However, there is also the context, and the reason why a person is defending a certain idea. Thrasymachus is not defending his position because he wants correct argumentation, but because he has to defend his people against the potential new oppression by the Athenians.
At the philosophical café, too, correct argumentation is an important component. But reflecting on the motivation of the participants to defend a particular position is another important component necessary for comprehending and moderating the discussion.