Defend people who aren’t in the room. Word gets back, and so does the silence.

Rooms leak. What gets repeated is not only what you said but also what you did not say, and people are surprisingly good at learning who stayed quiet while they were being discussed. Defending somebody absent costs you a moment of friction with whoever is present. Not defending them costs you something slower and harder to repair.

The useful line is short and does not have to be a confrontation. Saying that has not been your experience of them is usually enough to change the temperature. Try it once this week in a conversation where somebody is being taken apart.