He was fasting for days because of their wickedness, but he didn't hate them for how they treated him. He was concerned for the walfare of their souls. Alma was told to go back to the city and was led to Amulet who the spirit of the Lord had prepared to meet him.
Most of the people rejected the missionaries Alma and Amulek. Those who did repent were ejected from the city and their families were gathered together and burnt. This mission might have seemed in some aspects as a failure, but it produced to men who became might leaders in the church and great missionaries in there own right, Amulek and Zeezrum.
Amulek was rightous enough to recieve a holy message to prepare him for Almas arrival. He might have been saved without Alma's return. Zeezorom was a wicked lawyer who tried to trick the missionaries when he first met them. If Ammonihah had been destroyed with out a return visit of Alma Zeezrom and many others could have been destroyed. How would have that changed Nephite history. Remember when Alma assembles the Missionary All-stars that to witness to the fallen Zoramites, it includes Zeezrum.
It all starts when Alma is rejected from a city and prays for salvation for the very people that had just sent him packing. Now that is an amazing example of Charity. May we all do as little more for others and receive a little more charity in our hearts to share with those around us.