Kahvi at least just came in looking to intimidate her way to the prize. She scared the Sunfolk out of their wits and wrecked a couple of houses, but at least she didn't attack the Sunfolk themselves. I'm not saying that excuses Kahvi's aggression, but it does leave me willing to cut her some slack.
Zey, on the other hand, came in looking to cut a bloody path to the little palace, and this was after betraying his chief and running the Go Backs into the ground in Kahvi's absence. More than his attack on Sorrow's End, I despise Zey for allowing the Go-Backs to backslide. Go Backs aren't known for grand dreams; they tend to think in short, straight lines. At least under Kahvi, they had a goal -- find the Palace, keep the Palace. Under Zey, they weren't going anythere. They just fighting for the sake of fighting, because they'd never known anything else. Kahvi called him on that and his pride couldn't take the hit.