The Conquest of Makka by Khaled Ibn Wali

Khaled ibn Wali was camped in makka when news came to him that a large army was gathering outside of makka. He said alayisam min kumra julun rahaim wasn't there anybody who had mercy in his heart to stop this Khaled doing this right so this really demonstrates that. Some have said that Thawif assumed that the Prophet system was going to attack them rather than makka but this seems to be a bit of a stretch because why would the process of attack the citadel of Thawif?