Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
(How) this is also said by way of astonishment: how can there be any treaty between you and them (when, if they have the upper hand of you) they were to conquer you, (they regard no pact) they would have no regard for the ties of kinship relating you ; it is also said: they would have no regard for you in respect of Allah (nor honour about you?) because of the treaty between you. (They satisfy you with their mouths) with their tongues (the while their hearts refuse) while their hearts are averse to it. (And most of them) all of them (are wrong-doers) breakers of treaties.
How, can they have a pact, when, if they get the better of you, [if] they have the upper hand over you, they do not respect, [they do not] take into consideration, any bond, kinship, or treaty, pact, with regard to you, but will instead harm you as much as they can (the conditional sentence [‘if they …’] is [also] a circumstantial qualifier), pleasing you with their tongues, with charming words, while their hearts refuse, to be true to these [words]; and most of them are wicked, violators of pacts.
Allah encourages the believers to show enmity to the idolators andto dissociate from them, affirming that they do not deserve to enjoy a covenant of peace, because of their Shirk in Allah and disbelief in Allah's Messenger.
Allah encourages the believers to show enmity to the idolators and to dissociate from them, affirming that they do not deserve to enjoy a covenant of peace, because of their Shirk in Allah and disbelief in Allah's Messenger If these disbelievers have a chance to defeat Muslims, they will cause great mischief, leave nothing unharmed, disregard the ties of kinship and the sanctity of their vows. `Ali bin Abi Talhah, `Ikrimah and Al-`Awfi narrated that Ibn `Abbas said, "Ill means kinship, while, Dhimmah means covenant.'' Ad-Dahhak and As-Suddi said similarly.
Maududi - Sayyid Abul Ala Maududi - Tafhim al-Qur'an
That is: Bani Kinanah and Bani Khuza`ah and Bani Damrah.
That is, "Though outwardly they negotiated for peace treaties, they cherished evil intentions in their hearts, and waited for an opportune moment to break them. And this was borne by later experiences."
They were evil-doers because they had no sense of moral responsibilities nor did they hesitate to break moral limits.