To mock with the good quality
For example, when you say, “al-Kareem (the generous person)”, but you don’t mean it in a good way. You mean the person who shows off, or you’re saying / you’re implying, shows off with their sadaqa. So you say, “Oh, there goes the kareem one again”, “There goes the generous guy again.” Right? So you’re not actually talking about their generosity or praising it, but you’re mocking them to suggest that their good quality is insincere. That’s also under, “وَلَا تَنَابَزُوا بِالْأَلْقَابِ”.
And sometimes when people cannot realize a good quality themselves, they make themselves feel better by saying that those who exhibit those good qualities are not sincere in those good qualities.
So when they saw the Abu Bakrs of the world, and the Abd al-Rahman ibn Awfs of the world, they say, “Yeah. We know what they’re really up to.” Because they are people of moral bankruptcy, and so they assume that everybody else is morally bankrupt too.
Mock them for their good quality, that way, you make the good quality a bad quality, and you take away any responsibility from doing it yourself.