Khalid bin Walid was the hero during the Apostasy wars under Caliph Abu Bakr. Khalid was known for his brutality and it's estimated that 70,000 people were killed for attempting to leave Islam after Mohammad died. Many of these people had their eyes gouged out (supposedly even Bakr was horrified). This type of barbaric cruelty is permitted in Islam and has been going on for 1400 years. These murderers were doing what they are commanded to do in Islam and are, in fact, obedient Muslims.