Why does the Arab’s crime revolt Daru? Why then does he treat the Arab as his guest?

Daru abhors any act of violence, especially when it is not warranted. Daru, however, treats the Arab as a guest rather than a prisoner. Daru feels like the French are imposing their will on Arabs. Daru, who desperately wants to be accepted as an Arab, feels sympathy for him. This is the Arab's country and Daru is the outsider.