When they told it to Jotham, he went and stood on the top of Mount Gerizim, and lifted up his voice, and cried, and said to them, Listen to me, you men of Shechem, that God may listen to you.
In other words, he's an outsider. We ought to be serving Hamor and his family, let them be the kings. And he said to God the people were under my rule, because I can really do a good job here, you know. Who's Abimelech? And so he said if you would just commit yourself to me I would remove Abimelech.