Because he's his Father......?
Harald just went on a rampage where he killed his own people, and he was almost crying about how he was the worst king in Elbaf history. He wants Loki to kill him ASAP, and not cause him or anyone else anymore trouble. Again, similar to the fact that Xebec basically accepted death after DR. They're parallels.
Loki overpowered Harald in a 1v1, until he regained control. Gaban didn't believe it was possible.