Joshua 9:18

‘ And the children of Israel did not smite them, because the princes of the congregation had sworn unto them by YHWH the God of Israel. And all the congregation murmured against the princes.'

True to their treaty-covenant the Gibeonites were spared. Such a treaty was totally binding and unbreakable. But the people themselves were not happy. They wanted to get their own back on these Gibeonites who had made such fools of them, but the princes would not let them.