What was the wisdom behind the Prophet's command to kill the four on the day of the Conquest of Mecca?

The reasons for the Prophet, peace and blessings be upon him, ordering the killing of four individuals differed: Ikrimah ibn Abi Jahl, Abdullah ibn Khatal, Miqyas ibn Subabah, and Abdullah ibn Sa'd ibn Abi Sarh. Some of them apostatized and killed a Muslim, while another apostatized and claimed that he used to divert the Prophet from the words of revelation and write something other than what was revealed. Others were intensely hostile to the Messenger of Allah, peace and blessings be upon him. Ikrimah and Abdullah ibn Sa'd ibn Abi Sarh embraced Islam after the فتح (conquest) and their Islam became good, whereas Ibn Khatal and Miqyas were killed.