Matthew Poole and continuators on Joshua 9:18

18 And the children of Israel smote them not, because the princes of the congregation had sworn unto them by the LORD God of Israel: and all the congregation murmured against the Princes .

Partly from that proneness which is in people to censure the actions of their Rulers; partly because they might think the Princes by their rashness had brought them into a Snare, that they could neither Kill them for fear of the Oath, nor Spare them for fear of Gods Command to the contrary; and partly from their desire of the Possession and Spoil of these Cities, of which they thought themselves hereby deprived.