Responsa על שבועות 77:27

Let us now see how many excuses Israel had to cancel this oath: a) The two spies swore. Is the entire people of Israel obligated to confirm and uphold the oath? b) The spies themselves were coerced at the time. Their lives were in danger if they did not heed her. Had they not wanted to swear, she would have gone and disclosed that spies were afoot, and they would have been sentenced to death. c) Their oath does not take effect for those who are oath-bound to safeguard the word of the King on the matter of the oath to God: “you shall not let a soul remain alive. You must doom them to destruction.” d) She, her family, and all those who accompanied her were idolaters. e) The seven nations were wicked and sinful against God, and they perpetrated all manner of abomination that God hates.