Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
(How) this is said by way of astonishment (can there be a treaty with Allah and with His messenger for the idolaters save those with whom ye made a treaty at the Inviolable Place of Worship?) after the year of al-Hudaybiyyah, the reference here is to the Banu Kinanah. (So long as they are true to you) in that they honour their treaty, (be true to them) completely. (Lo! Allah loveth those who keep their duty) and abstain from breaking their treaties.
How can the idolaters have a pact with God and His Messenger — they cannot —while they disbelieve in God and His Messenger, acting treacherously; except for those with whom you made a pact at the Sacred Mosque?, the day of al-Hudaybiyya — these were Quraysh, for whom an exception was made earlier [Q. 9:4]. So long as they are true to you, keeping to the pact and not breaking it, be true to them, by fulfilling it (fa-mā, ‘so long as’: the mā is a conditional particle). Truly God loves the God-fearing: the Prophet (s) had kept to the pact made with them until they broke it by supporting the Banū Bakr against Khuzā‘a.
(then stand you true to them. Verily, Allah loves those who have Taqwa.) The Messenger of Allah and the Muslims preserved the terms of the treaty with the people of Makkah from the month of Dhul-Qa`dah in the sixth year of Hijrah, until the Quraysh broke it and helped their allies, Banu Bakr, against Khuza`ah, the allies of Allah's Messenger. Aided by the Quraysh, Banu Bakr killed some of Bani Khuza`ah in the Sacred Area! The Messenger of Allah led an invasion army in the month of Ramadan, of the eighth year, and Allah opened the Sacred Area for him to rule over them, all thanks are due to Allah. The Messenger of Allah freed the Quraysh who embraced Islam after they were overpowered and defeated. These numbered around two thousands, and they were refered to by the name `Tulaqa' afterwards. Those among them who remained in disbelief and ran away from Allah's Messenger were sent promises of safe refuge for four months, during which they were allowed to move about freely. They included Safwan bin Umayyah, `Ikrimah bin Abi Jahl and many others. Allah later on guided them to Islam, and they became excellent believers. Surely, Allah is worthy of all praise for all His actions and decrees.
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.